US20230114717A1 - Kinetic Suspension System With Incremental Roll And Pitch Stiffness Control - Google Patents
Kinetic Suspension System With Incremental Roll And Pitch Stiffness Control Download PDFInfo
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- US20230114717A1 US20230114717A1 US17/499,705 US202117499705A US2023114717A1 US 20230114717 A1 US20230114717 A1 US 20230114717A1 US 202117499705 A US202117499705 A US 202117499705A US 2023114717 A1 US2023114717 A1 US 2023114717A1
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Definitions
- the present disclosure relates generally to suspension systems for motor vehicles and more particularly to suspension systems and associated control methods that resist the pitch and roll movements of a vehicle by making incremental adjustments to target pressure and stiffness.
- Suspension systems improve the ride of a vehicle by absorbing bumps and vibrations that would otherwise unsettle the vehicle body. Suspension systems also improve safety and control by improving contact between the ground and the tires of the vehicle.
- One drawback of suspension systems is that basic spring / damper arrangements will allow the vehicle to roll / lean right or left during cornering (e.g., in turns), pitch forward under deceleration (e.g., under braking), and pitch back under acceleration. The lateral acceleration the vehicle experiences in turns causes a roll moment where the vehicle will lean / squat to the right when turning left and to the left when turning right.
- anti-roll bars are mechanical systems that help counteract the roll moments experienced during driving.
- anti-roll bars are typically mechanical linkages that extend laterally across the width of the vehicle between the right and left dampers. When one of the dampers extends, the anti-roll bar applies a force to the opposite damper that counteracts the roll moment of the vehicle and helps to correct the roll angle to provide flatter cornering.
- anti-roll suspension systems are being developed that hydraulically connect two or more dampers in a hydraulic circuit where the extension of one damper produces a pressure change in the other damper(s) in the hydraulic circuit that makes it more difficult to compress the other damper(s) in the hydraulic circuit.
- This pressure change in the other damper(s) increases the roll and pitch stiffness of the suspension system of the vehicle.
- the internal pressure in the hydraulic circuits, and thus the roll and pitch stiffness changes with temperature. For example, the internal pressure in the hydraulic circuits will rise as temperature increases, which will increase the roll and pitch stiffness of the suspension system. The opposite is true for when there is a temperature decrease. Accordingly, there is a need for a suspension system that can maintain a specified target pressure and target stiffness, regardless of temperature changes, without significant spikes or drops in pressure in the hydraulic circuits as adjustments are made.
- a method of controlling a suspension system of a vehicle includes connecting a manifold assembly to a plurality of dampers via a plurality of hydraulic circuits and connecting the manifold assembly to a pump assembly via a pump hydraulic line.
- the manifold assembly includes one or more manifold valves that are configured to control fluid flow between the pump hydraulic line and the hydraulic circuits.
- the pump assembly includes a pump that is arranged in fluid communication with the pump hydraulic line.
- the method includes the steps of setting a target stiffness and a target pressure in a suspension control unit (SCU) of the suspension system and monitoring real-time data from one or more onboard sensors or systems.
- SCU suspension control unit
- the real-time data that is monitored by the suspension control unit (SCU) includes data reflecting fluid pressure within one or more of the hydraulic circuits, damper displacement for one or more of the dampers, lateral acceleration of the vehicle, and/or longitudinal acceleration of the vehicle.
- the method further includes the steps of determining an effective stiffness of the suspension system based on the real-time data, determining if the effective stiffness of the suspension system is above or below the target stiffness, and setting a new target pressure in the suspension control unit (SCU) if the effective stiffness is determined to be above or below the target stiffness.
- the suspension control unit (SCU) performs the step of setting a new target pressure by making a stepwise decrease or increase to the target pressure, depending on whether the effective stiffness is above or below the target stiffness.
- the method proceeds with the steps of opening the manifold valve(s), energizing the pump in a first direction or a second direction to pump hydraulic fluid into or out of the hydraulic circuits of the suspension system until the new target pressure is reached, and closing the manifold valve(s) when the new target pressure is reached.
- the method then reiterates aforementioned steps until the effective stiffness falls within a pre-determined range of the target stiffness.
- the method of controlling the suspension system of the vehicle further includes the steps of setting a target roll stiffness, a target pitch stiffness, and the target pressure in a suspension control unit (SCU) of the suspension system and determining an effective roll stiffness and an effective pitch stiffness of the suspension system based on the real-time data.
- the method includes the steps of determining if the effective roll stiffness is below the target roll stiffness, determining if the effective pitch stiffness is below the target pitch stiffness, and setting a new target pressure in the suspension control unit (SCU) by making a stepwise increase to the target pressure if the effective roll stiffness is below the target roll stiffness or if the effective pitch stiffness is below the target pitch stiffness.
- the method proceeds with the steps of opening the manifold valve(s) and energizing the pump in a first direction to pump hydraulic fluid into the hydraulic circuits of the suspension system until the new target pressure is reached.
- the method also includes the steps of determining if the effective roll stiffness is above the target roll stiffness, determining if the effective pitch stiffness is above the target pitch stiffness, and setting a new target pressure in the suspension control unit (SCU) by making a stepwise decrease to the target pressure if the effective roll stiffness is above the target roll stiffness or if the effective pitch stiffness is above the target pitch stiffness.
- the method proceeds with the steps of opening the manifold valve(s) and energizing the pump in a second direction to pump hydraulic fluid out of the hydraulic circuits of the suspension system until the new target pressure is reached.
- the method proceeds with closing the manifold valve(s) when the new target pressure is reached and reiterating the aforementioned steps until the effective roll stiffness and the effective pitch stiffness fall within a pre-determined range of the target roll stiffness and the target pitch stiffness.
- a suspension system of a vehicle includes a manifold assembly that is connected in fluid communication with a plurality of dampers via a plurality of hydraulic circuits and that is connected in fluid communication with a pump assembly via a pump hydraulic line.
- the manifold assembly includes one or more manifold valves that are configured to control fluid flow between the pump hydraulic line and the hydraulic circuits.
- the pump assembly includes a pump that is arranged in fluid communication with the pump hydraulic line.
- the suspension system also includes one or more onboard sensors that are configured to generate real-time data regarding the vehicle and a suspension control unit (SCU) that is arranged in electronic communication with the manifold valve(s), the pump, and the onboard sensor(s).
- SCU suspension control unit
- the suspension control unit (SCU) includes a processor and memory that is configured to monitor the real-time data generated by the onboard sensor(s) and set a target stiffness and a target pressure in the memory.
- the suspension control unit (SCU) is programmed to: determine an effective stiffness of the suspension system based on the real-time data, determine if the effective stiffness of the suspension system is above or below the target stiffness, set a new target pressure in the memory of the suspension control unit (SCU) if the effective stiffness is determined to be above or below the target stiffness by making a stepwise decrease or increase to the target pressure, open the manifold valve(s) when the new target pressure is set by the suspension control unit (SCU), energize the pump in a first direction or a second direction to pump hydraulic fluid into or out of the hydraulic circuits of the suspension system until the new target pressure is reached, and close the manifold valve(s) when the new target pressure is reached.
- the suspension system of the present disclosure is able to reduce / eliminate vehicle roll while cornering and vehicle pitch during acceleration and braking for improved grip, performance, handling, and braking.
- the reduction of roll and pitch angles improves the comfort, steering feel, agility, and stability of the vehicle.
- Roll and pitch control is provided by increasing or decreasing the roll and pitch stiffness of the suspension system (based on static pressure in the system).
- the level of roll and pitch stiffness can be adjusted by using the pump to change the static pressure in select hydraulic circuits of the suspension system.
- the suspension system and control methods described herein can address changes in the static pressure due to increases and decreases in temperature.
- the suspension system and methods described herein can deliver target roll and/or pitch stiffness more accurately and are less susceptible to temperature related fluctuations in internal pressure and stiffness.
- FIG. 1 is a schematic diagram illustrating an exemplary suspension system of the present disclosure that includes two comfort valves that open and close the hydraulic lines connecting the two front dampers to the two rear dampers of the system;
- FIG. 2 is a schematic diagram illustrating another exemplary suspension system of the present disclosure that includes two comfort valves that open and close the hydraulic lines connecting the two front dampers to the two rear dampers of the system and a separate hydraulic lifting circuit for the two front dampers;
- FIG. 3 is a schematic diagram illustrating another exemplary suspension system of the present disclosure that includes two comfort valves that open and close the hydraulic lines connecting the two front dampers to the two rear dampers of the system and two separate hydraulic lifting circuits for the two front dampers and the two rear dampers;
- FIG. 4 is a schematic diagram illustrating another exemplary suspension system of the present disclosure that includes four hydraulic circuits connecting the front and rear dampers and an exemplary comfort valve equipped manifold assembly;
- FIG. 5 is a schematic diagram illustrating the exemplary comfort valve equipped manifold assembly illustrated in FIG. 4 ;
- FIG. 6 is a schematic diagram illustrating another exemplary suspension system of the present disclosure that includes four hydraulic circuits connecting the front and rear dampers and another exemplary comfort valve equipped manifold assembly;
- FIG. 7 is a schematic diagram illustrating another exemplary suspension system of the present disclosure that includes four hydraulic circuits connecting the front and rear dampers and another exemplary comfort valve equipped manifold assembly;
- FIG. 8 is a schematic diagram illustrating a vehicle equipped with an exemplary suspension control system in accordance with the present disclosure.
- FIG. 9 is a flow diagram illustrating an exemplary method of controlling the exemplary suspension systems described in the present disclosure.
- Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
- first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
- Spatially relative terms such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures.
- Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features.
- the example term “below” can encompass both an orientation of above and below.
- the device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
- a suspension system 100 including a front left damper 102 a , a front right damper 102 b , a back left damper 102 c , and a back right damper 102 d . While it should be appreciated that the suspension system 100 described herein may include a different number of dampers than those shown in the drawings, in most automotive applications, four dampers are used at each corner of a vehicle to control vertical movements of the front and rear wheels of the vehicle.
- the front left damper 102 a controls (e.g., dampens) up and down (i.e., vertical) movements of the front left wheel of the vehicle
- the front right damper 102 b controls (e.g., dampens) up and down (i.e., vertical) movements of the front right wheel of the vehicle
- the back left damper 102 c controls (e.g., dampens) up and down (i.e., vertical) movements of the back left wheel of the vehicle
- the back right damper 102 d controls (e.g., dampens) up and down (i.e., vertical) movements of the back right wheel of the vehicle.
- the suspension system 100 also includes a manifold assembly 104 that is connected in fluid communication with a pump assembly 106 by a pump hydraulic line 108 .
- the pump assembly 106 includes a bi-directional pump 110 , a hydraulic reservoir 112 (e.g., a tank), and a bypass hydraulic line 114 that can be open and closed by a pressure relief valve 116 .
- the bi-directional pump 110 includes a first inlet/outlet port that is connected to the pump hydraulic line 108 and a second inlet/outlet port that is connected in fluid communication with the hydraulic reservoir 112 by a reservoir hydraulic line 118 .
- the bi-directional pump 110 may operate (i.e., pump fluid) in two opposite directions depending on the polarity of the electricity that is supplied to the pump 110 , so the first inlet/outlet port may operate as either an inlet port or an outlet port depending on the direction the bi-directional pump 110 is operating in and the same is true for the second inlet/outlet port of the bi-directional pump 110 .
- the bi-directional pump 110 draws in hydraulic fluid from the pump hydraulic line 108 via the first inlet/outlet port and discharges hydraulic fluid into the reservoir hydraulic line 118 via the second inlet/outlet port.
- the bi-directional pump 110 produces a negative pressure in the pump hydraulic line 108 that can be used by manifold assembly 104 to reduced fluid pressure in the suspension system 100 .
- the bi-directional pump 110 draws in hydraulic fluid from the reservoir hydraulic line 118 via the second inlet/outlet port and discharges hydraulic fluid into the pump hydraulic line 108 via the first inlet/outlet port.
- the bi-directional pump 110 produces a positive pressure in the pump hydraulic line 108 that can be used by manifold assembly 104 to increase fluid pressure in the suspension system 100 .
- the bypass hydraulic line 114 runs from the pump hydraulic line 108 to the hydraulic reservoir 112 and bleeds fluid back into the hydraulic reservoir 112 when the pressure in the pump hydraulic line 108 exceeds a threshold pressure that causes the pressure relief valve 116 to open.
- the manifold assembly 104 is connected in fluid communication with the front and rear dampers 102 a , 102 b , 102 c , 102 d by first and second hydraulic circuits 120 a , 120 b .
- the manifold assembly 104 includes first and second manifold valves 122 a , 122 b that are connected in parallel with the pump hydraulic line 108 .
- the first hydraulic circuit 120 a is connected in fluid communication with the first manifold valve 122 a and the second hydraulic circuit 120 b is connected in fluid communication with the second manifold valve 122 b .
- the manifold assembly 104 also includes a first pressure sensor 124 a that is arranged to monitor the pressure in the first hydraulic circuit 120 a and a second pressure sensor 124 b that is arranged to monitor the pressure in the second hydraulic circuit 120 b .
- the bi-directional pump 110 of the pump assembly 106 and first and second pressure sensors 124 a , 124 b and the first and second manifold valves 122 a , 122 b of the manifold assembly 104 are electrically connected to a controller (not shown), which is configured to activate (i.e., turn on in forward or reverse) the bi-directional pump 110 and electronically actuate (i.e., open and close) the first and second manifold valves 122 a , 122 b in response to various inputs, including signals from the first and second pressure sensors 124 a , 124 b .
- the controller opens the first and second manifold valves 122 a , 122 b , the fluid pressure in the first and second hydraulic circuit
- suspension system 100 The anti-roll capabilities of the suspension system 100 will be explained in greater detail below; however, from FIG. 1 it should be appreciated that fluid pressure in the first and second hydraulic circuits 120 a , 120 b operate to dynamically adjust the roll stiffness of the vehicle and can be used to either augment or completely replace mechanical stabilizer bars / anti-roll bars.
- Such mechanical systems require relatively straight, unobstructed runs between each of the front dampers 102 a , 102 b and each of the back dampers 102 c , 102 d .
- the suspension system 100 disclosed herein offers packaging benefits because the dampers 102 a , 102 b , 102 c , 102 d only need to be hydraulically connected to the manifold assembly 104 .
- Each of the dampers 102 a , 102 b , 102 c , 102 d of the suspension system 100 includes a damper housing, a piston rod, and a piston that is mounted on the piston rod.
- the piston is arranged in sliding engagement with the inside of the damper housing such that the piston divides the damper housing into compression and rebound chambers.
- the front left damper 102 a includes a first compression chamber 126 a and a first rebound chamber 128 a
- the front right damper 102 b includes a second compression chamber 126 b and a second rebound chamber 128 b
- the back left damper 102 c includes a third compression chamber 126 c and a third rebound chamber 128 c
- the back right damper 102 d includes a fourth compression chamber 126 d and a fourth rebound chamber 128 d .
- the piston is a closed piston with no fluid flow paths defined within or by its structure.
- there are no other fluid flow paths in the damper housing such that no fluid is communicated between the compression and rebound chambers of the dampers 102 a , 102 b , 102 c , 102 d except through the first and second hydraulic circuits 120 a , 120 b .
- the rebound chambers 128 a , 128 b , 128 c , 128 d of the dampers 102 a , 102 b , 102 c , 102 d decrease in volume during rebound / extension strokes and increase in volume during compression strokes of the dampers 102 a , 102 b , 102 c , 102 d .
- the compression chambers 126 a , 126 b , 126 c , 126 d of the dampers 102 a , 102 b , 102 c , 102 d decrease in volume during compression strokes of the dampers 102 a , 102 b , 102 c , 102 d and increase in volume during rebound / extension strokes of the dampers 102 a , 102 b , 102 c , 102 d .
- Each damper 102 a , 102 b , 102 c , 102 d also includes rebound and compression chamber ports 130 a , 130 b in the damper housing that are each provided with dampening valves.
- the rebound chamber port 130 a is arranged in fluid communication with the rebound chamber 128 a , 128 b , 128 c , 128 d of the damper 102 a , 102 b , 102 c , 102 d and the second port 130 b is arranged in fluid communication with the compression chamber 126 a , 126 b , 126 c , 126 d of the damper 102 a , 102 b , 102 c , 102 d .
- the dampening valves in the rebound and compression chamber ports 130 a , 130 b can be passive / spring-biased valves (e.g., spring-disc stacks) or active valves (e.g., electromechanical valves) and control fluid flow into and out of the compression and rebound chambers of the dampers 102 a , 102 b , 102 c , 102 d to provide one or more rebound dampening rates and compression dampening rates for each of the dampers 102 a , 102 b , 102 c , 102 d .
- passive / spring-biased valves e.g., spring-disc stacks
- active valves e.g., electromechanical valves
- the first hydraulic circuit 120 a includes a first longitudinal hydraulic line 132 a that extends between and fluidly connects the second port 130 b (to the first compression chamber 126 a ) of the front left damper 102 a and the second port 130 b (to the third compression chamber 126 c ) of the back left damper 102 c .
- the first hydraulic circuit 120 a includes a front hydraulic line 134 a that extends between and fluidly connects the first longitudinal hydraulic line 132 a and the rebound chamber port 130 a (to the second rebound chamber 128 b ) of the front right damper 102 b .
- the first hydraulic circuit 120 a also includes a rear hydraulic line 136 a that extends between and fluidly connects the first longitudinal hydraulic line 132 a and the rebound chamber port 130 a (to the fourth rebound chamber 128 d ) of the back right damper 102 d .
- the first hydraulic circuit 120 a further includes a first manifold hydraulic line 138 a that extends between and fluidly connects the first longitudinal hydraulic line 132 a and the first manifold valve 122 a .
- the second hydraulic circuit 120 b includes a second longitudinal hydraulic line 132 b that extends between and fluidly connects the compression chamber port 130 b (to the second compression chamber 126 b ) of the front right damper 102 b and the compression chamber port 130 b (to the fourth compression chamber 126 d ) of the back right damper 102 d .
- the second hydraulic circuit 120 b includes a front hydraulic line 134 b that extends between and fluidly connects the second longitudinal hydraulic line 132 b and the rebound chamber port 130 a (to the first rebound chamber 128 a ) of the front left damper 102 a .
- the second hydraulic circuit 120 b also includes a rear hydraulic line 136 b that extends between and fluidly connects the second longitudinal hydraulic line 132 b and the rebound chamber port 130 a (to the third rebound chamber 128 c ) of the back left damper 102 c .
- the second hydraulic circuit 120 b further includes a second manifold hydraulic line 138 b that extends between and fluidly connects the second longitudinal hydraulic line 132 b and the second manifold valve 122 b .
- first and second longitudinal hydraulic lines 132 a , 132 b simply means that the first and second longitudinal hydraulic lines 132 a , 132 b run between the front dampers 102 a , 102 b and the back dampers 102 c , 102 d generally.
- the first and second longitudinal hydraulic lines 132 a , 132 b need not be linear or arranged in any particular direction as long as they ultimately connect the front dampers 102 a , 102 b and the back dampers 102 c , 102 d .
- the suspension system 100 also includes four bridge hydraulic lines 140 a , 140 b , 140 c , 140 d that fluidly couple the first and second hydraulic circuits 120 a , 120 b and each corner of the vehicle.
- the four bridge hydraulic lines 140 a , 140 b , 140 c , 140 d include a front left bridge hydraulic line 140 a that extends between and fluidly connects the first longitudinal hydraulic line 132 a of the first hydraulic circuit 120 a and the front hydraulic line 134 b of the second hydraulic circuit 120 b , a front right bridge hydraulic line 140 b that extends between and fluidly connects the front hydraulic line 134 a of the first hydraulic circuit 120 a and the second longitudinal hydraulic line 132 b of the second hydraulic circuit 120 b , a back left bridge hydraulic line 140 c that extends between and fluidly connects the first longitudinal hydraulic line 132 a of the first hydraulic circuit 120 a and the rear hydraulic line 136 b of the second hydraulic circuit 120 b , and a back right bridge hydraulic line 140
- the front left bridge hydraulic line 140 a is connected to the first longitudinal hydraulic line 132 a between the compression chamber port 130 b of the front left damper 102 a and the front hydraulic line 134 a of the first hydraulic circuit 120 a .
- the front right bridge hydraulic line 140 b is connected to the second longitudinal hydraulic line 132 b between the compression chamber port 130 b of the front right damper 102 b and the front hydraulic line 134 b of the second hydraulic circuit 120 b .
- the back left bridge hydraulic line 140 c is connected to the first longitudinal hydraulic line 132 a between the compression chamber port 130 b of the back left damper 102 c and the rear hydraulic line 136 a of the first hydraulic circuit 120 a .
- the back right bridge hydraulic line 140 d is connected to the second longitudinal hydraulic line 132 b between the compression chamber port 130 b of the back right damper 102 d and the rear hydraulic line 136 b of the second hydraulic circuit 120 b .
- the various hydraulic lines are made of flexible tubing (e.g., hydraulic hoses), but it should be appreciated that other conduit structures and/or fluid passageways can be used.
- a front left accumulator 142 a is arranged in fluid communication with the first longitudinal hydraulic line 132 a at a location between the compression chamber port 130 b of the front left damper 102 a and the front left bridge hydraulic line 140 a .
- a front right accumulator 142 b is arranged in fluid communication with the second longitudinal hydraulic line 132 b at a location between the compression chamber port 130 b of the front right damper 102 b and the front right bridge hydraulic line 140 b .
- a back left accumulator 142 c is arranged in fluid communication with the first longitudinal hydraulic line 132 a at a location between the compression chamber port 130 b of the back left damper 102 c and the back left bridge hydraulic line 140 c .
- a back right accumulator 142 d is arranged in fluid communication with the second longitudinal hydraulic line 132 b at a location between the compression chamber port 130 b of the back right damper 102 d and the back right bridge hydraulic line 140 d .
- Each of the accumulators 142 a , 142 b , 142 c , 142 d have a variable fluid volume that increases and decreases depending on the fluid pressure in the first and second longitudinal hydraulic lines 132 a , 132 b .
- the accumulators 142 a , 142 b , 142 c , 142 d may be constructed in a number of different ways.
- the accumulators 142 a , 142 b , 142 c , 142 d may have accumulation chambers and pressurized gas chambers that are separated by floating pistons or flexible membranes.
- the suspension system 100 also includes six electro-mechanical comfort valves 144 a , 144 b , 144 c , 144 d , 146 a , 146 b that are connected in-line (i.e., in series) with each of the bridge hydraulic lines 140 a , 140 b , 140 c , 140 d and each of the longitudinal hydraulic lines 132 a , 132 b .
- a front left comfort valve 144 a is positioned in the front left bridge hydraulic line 140 a .
- a front right comfort valve 144 b is positioned in the front right bridge hydraulic line 140 b .
- a back left comfort valve 144 c is positioned in the back left bridge hydraulic line 140 c .
- a back right comfort valve 144 d is positioned in the back right bridge hydraulic line 140 d .
- a first longitudinal comfort valve 146 a is positioned in the first longitudinal hydraulic line 132 a between the front and rear hydraulic lines 134 a , 136 a of the first hydraulic circuit 120 a .
- a second longitudinal comfort valve 146 b is positioned in the second longitudinal hydraulic line 132 b between the front and rear hydraulic lines 134 b , 136 b of the second hydraulic circuit 120 b .
- the comfort valves 144 a , 144 b , 144 c , 144 d and the longitudinal comfort valves 146 a , 146 b are semi-active electro-mechanical valves with a combination of passive spring-disk elements and a solenoid.
- the comfort valves 144 a , 144 b , 144 c , 144 d and the longitudinal comfort valves 146 a , 146 b are electronically connected to the controller, which is configured to supply electrical current to the solenoids of the comfort valves 144 a , 144 b , 144 c , 144 d and the longitudinal comfort valves 146 a , 146 b to selectively and individually open and close the comfort valves 144 a , 144 b , 144 c , 144 d and the longitudinal comfort valves 146 a , 146 b .
- the first pressure sensor 124 a of the manifold assembly 104 is arranged to measure fluid pressure in the first manifold hydraulic line 138 a and the second pressure sensor 124 b of the manifold assembly 104 is arranged to measure fluid pressure in the second manifold hydraulic line 138 b .
- the lateral and longitudinal acceleration is measured by one or more accelerometers (not shown) and the anti-roll torque to control the roll of the vehicle is calculated by the controller.
- the lateral and longitudinal acceleration of the vehicle can be computed by the controller based on a variety of different inputs, including without limitation, steering angle, vehicle speed, brake pedal position, and/or accelerator pedal position.
- the dampers 102 a , 102 b , 102 c , 102 d are used to provide forces that counteract the roll moment induced by the lateral acceleration, thus reducing the roll angle of the vehicle.
- the first and second hydraulic circuits 120 a , 120 b operate as a closed loop system, either together or separately depending on the open or closed status of the electro-mechanical comfort valves 144 a , 144 b , 144 c , 144 d and the longitudinal comfort valves 146 a , 146 b .
- the bi-directional pump 110 either adds or removes fluid from the first and/or second hydraulic circuits 120 a , 120 b .
- the suspension system 100 can control the roll stiffness of the vehicle, which changes the degree to which the vehicle will lean to one side or the other during corning (i.e., roll)
- the front right damper 102 b and back right damper 102 d begin to extend, causing fluid to flow out of the second rebound chamber 128 b of the front right damper 102 b and the fourth compression chamber 126 d of the back right damper 102 d into the front and rear hydraulic lines 134 a , 136 a of the first hydraulic circuit 120 a .
- the resulting pressure difference between the dampers 102 a , 102 b , 102 c , 102 d generates damper forces that counteract or resist the roll moment of the vehicle.
- Additional roll resistance can be added by opening the first manifold valve 122 a as the bi-directional pump 110 is running in a first direction where the bi-directional pump 110 draws in hydraulic fluid from the reservoir hydraulic line 118 and discharges hydraulic fluid into the pump hydraulic line 108 to produce a positive pressure in the pump hydraulic line 108 , which increases fluid pressure in the first hydraulic circuit 120 a when the first manifold valve 122 a is open.
- the front left damper 102 a and back left damper 102 c begin to extend, causing fluid to flow out of the first rebound chamber 128 a of the front left damper 102 a and the third rebound chamber 128 c of the back left damper 102 c into the front and rear hydraulic lines 134 b , 136 b of the second hydraulic circuit 120 b .
- Additional roll resistance can be added by opening the second manifold valve 122 b as the bi-directional pump 110 is running in the first direction where the bi-directional pump 110 draws in hydraulic fluid from the reservoir hydraulic line 118 and discharges hydraulic fluid into the pump hydraulic line 108 to produce a positive pressure in the pump hydraulic line 108 , which increases fluid pressure in the second hydraulic circuit 120 b when the second manifold valve 122 b is open.
- the roll stiffness of the front dampers 102 a , 102 b can be coupled or de-coupled from the roll stiffness of the rear dampers 102 c , 102 d by opening and closing the first and/or second longitudinal comfort valves 146 a , 146 b .
- the roll stiffness of the front left damper 102 a and the back left damper 102 c will be coupled when the first longitudinal comfort valve 146 a is open and decoupled when the first longitudinal comfort valve 146 a is closed.
- the roll stiffness of the front right damper 102 b and the back right damper 102 d will be coupled when the second longitudinal comfort valve 146 b is open and decoupled when the second longitudinal comfort valve 146 b is closed.
- the comfort valves 144 a , 144 b , 144 c , 144 d and the longitudinal comfort valves 146 a , 146 b can be opened to enhance the ride comfort of the suspension system 100 and reduce or eliminate unwanted suspension movements resulting from the hydraulic coupling of one damper of the system to another damper of the system (e.g., where the compression of one damper causes movement and/or a dampening change in another damper).
- fluid may flow from the first compression chamber 126 a of the front left damper 102 a , into the first longitudinal hydraulic line 132 a , from the first longitudinal hydraulic line 132 a to the front hydraulic line 134 b of the second hydraulic circuit 120 b by passing through the front left bridge hydraulic line 140 a and the front left comfort valve 144 a , and into the first rebound chamber 128 a of the front left damper 102 a .
- fluid can travel from the first compression chamber 126 a to the first rebound chamber 128 a of the front left damper 102 a with the only restriction coming from the dampening valves in the rebound and compression chamber ports 130 a , 130 b of the front left damper 102 a .
- the dampers 102 a , 102 b , 102 c , 102 d are effectively decoupled from one another for improved ride comfort.
- the first and/or second manifold valves 122 a , 122 b may be opened while the bi-directional pump 110 is running in a second direction where the bi-directional pump 110 draws in hydraulic fluid from the pump hydraulic line 108 and discharges hydraulic fluid into the reservoir hydraulic line 118 to produce a negative pressure in the pump hydraulic line 108 that reduces fluid pressure in the first and/or second hydraulic circuits 120 a , 120 b .
- FIG. 2 illustrates another suspension system 200 that shares many of the same components as the suspension system 100 illustrated in FIG. 1 , but in FIG. 2 a front axle lift assembly 248 has been added. Rather than repeat the description set forth above, the following paragraphs describe the structure and function of the components in FIG. 2 that are new and/or different from those shown and described in connection with FIG. 1 .
- the reference numbers in FIG. 1 are “100” series numbers (e.g., 100, 102, 104, etc.) whereas the components in FIG. 2 that are the same or similar to the components of the suspension system 100 shown in FIG. 1 share the same base reference numbers, but are listed as “200” series numbers (e.g., 200, 202, 204, etc.).
- the same description for element 100 above applies to element 200 in FIG. 2 and so on and so forth.
- the front axle lift assembly 248 illustrated in FIG. 2 includes a front left lifter 250 a on the front left damper 202 a and a front right lifter 250 b on the front right damper 202 b .
- the front left damper 202 a and the front right damper 202 b include a front left coil spring 252 a and a front right coil spring 252 b , respectively, that extend co-axially and helically about the piston rods of the front dampers 202 a , 202 b in a coil-over arrangement.
- the front lifters 250 a , 250 b are positioned between the front coils springs 252 a , 252 b and the first and second rebound chambers 228 a , 228 b of the front dampers 202 a , 202 b and extend co-axially and annularly about the piston rods.
- the manifold assembly 204 further includes a third manifold valve 222 c that is connected in fluid communication with the pump hydraulic line 208 .
- a front axle lift hydraulic line 254 a extends between and is fluidly connected to the third manifold valve 222 c with the front left lifter 250 a and the front right lifter 250 b .
- a third pressure sensor 224 c is arranged to monitor the fluid pressure in the front axle lift hydraulic line 254 a .
- Each front lifter 250 a , 250 b is axially expandable such that an increase in fluid pressure inside the front lifters 250 a , 250 b causes the front lifters 250 a , 250 b to urge the front coil springs 252 a , 252 b away from the first and second rebound chambers 228 a , 228 b of the front dampers 202 a , 202 b , which operates to lift (i.e., raise) the front of the vehicle, increasing the ride height.
- the controller opens the third manifold valve 222 c when the bi-directional pump 210 is running in the first direction where the bi-directional pump 210 draws in hydraulic fluid from the reservoir hydraulic line 218 and discharges hydraulic fluid into the pump hydraulic line 208 to produce a positive pressure in the pump hydraulic line 208 , which increases fluid pressure in the front axle lift hydraulic line 254 a and thus the front lifters 250 a , 250 b .
- the controller closes the third manifold valve 222 c . It should therefore be appreciated that the front axle lift assembly 248 can be used to provide improved ground clearance during off-road operation or to give low riding vehicles improved ground clearance when traversing speed bumps.
- the controller opens the third manifold valve 222 c when the bi-directional pump 210 is running in the second direction where the bi-directional pump 210 draws in hydraulic fluid from the pump hydraulic line 208 and discharges hydraulic fluid into the reservoir hydraulic line 218 to produce a negative pressure in the pump hydraulic line 208 that reduces fluid pressure in the front axle lift hydraulic line 254 a to lower the front of the vehicle back down to an unlifted position.
- FIG. 3 illustrates another suspension system 300 that shares many of the same components as the suspension systems 100 , 200 illustrated in FIGS. 1 and 2 , but in FIG. 3 a rear axle lift assembly 356 has been added. Rather than repeat the description set forth above, the following paragraphs describe the structure and function of the components in FIG. 3 that are new and/or different from those shown and described in connection with FIGS. 1 and 2 . It should be appreciated that the reference numbers in FIG. 1 are “100” series numbers (e.g., 100, 102, 104, etc.) and the reference numbers in FIG. 2 are “200” series numbers (e.g., 200, 202, 204, etc.) whereas the components in FIG.
- the rear axle lift assembly 356 illustrated in FIG. 3 includes a back left lifter 350 c on the back left damper 302 c and a back right lifter 350 d on the back right damper 302 d .
- the back left damper 302 c and the back right damper 302 d include a back left coil spring 352 c and a back right coil spring 352 d , respectively, that extend co-axially and helically about the piston rods of the back dampers 302 c , 302 d in a coil-over arrangement.
- the back lifters 350 c , 350 d are positioned between the back coils springs 352 c , 352 d and the third and fourth rebound chambers 328 c , 328 d of the back dampers 302 a , 302 b and extend co-axially and annularly about the piston rods.
- the manifold assembly 304 further includes a fourth manifold valve 322 d that is connected in fluid communication with the pump hydraulic line 308 .
- a rear axle lift hydraulic line 354 b extends between and is fluidly connected to the fourth manifold valve 322 d with the back left lifter 350 c and the back right lifter 350 d .
- a fourth pressure sensor 324 d is arranged to monitor the fluid pressure in the rear axle lift hydraulic line 354 b .
- Each back lifter 350 c , 350 d is axially expandable such that an increase in fluid pressure inside the back lifters 350 c , 350 d causes the back lifters 350 c , 350 d to urge the back coil springs 352 c , 352 d away from the third and fourth rebound chambers 328 c , 328 d of the back dampers 302 c , 302 d , which operates to lift (i.e., raise) the back / rear of the vehicle, increasing the ride height.
- the controller opens the fourth manifold valve 322 d when the bi-directional pump 310 is running in the first direction where the bi-directional pump 310 draws in hydraulic fluid from the reservoir hydraulic line 318 and discharges hydraulic fluid into the pump hydraulic line 308 to produce a positive pressure in the pump hydraulic line 308 , which increases fluid pressure in the rear axle lift hydraulic line 354 b and thus the back lifters 350 c , 350 d .
- the controller closes the fourth manifold valve 322 d . It should therefore be appreciated that the rear axle lift assembly 356 can be used in combination with the front axle lift assembly 348 (also described above in connection with FIG.
- the controller opens the fourth manifold valve 322 D when the bi-directional pump 310 is running in the second direction where the bi-directional pump 310 draws in hydraulic fluid from the pump hydraulic line 308 and discharges hydraulic fluid into the reservoir hydraulic line 318 to produces a negative pressure in the pump hydraulic line 308 that reduces fluid pressure in the rear axle lift hydraulic line 354 b to lower the rear of the vehicle back down to an unlifted position.
- FIG. 4 another suspension system 400 is illustrated that shares many of the same components as the suspension system 100 illustrated in FIG. 1 . Rather than repeat the description set forth above, the following paragraphs describe the structure and function of the components in FIG. 4 that are new and/or different from those shown and described in connection with FIG. 1 .
- the reference numbers in FIG. 1 are “100” series numbers (e.g., 100, 102, 104, etc.) whereas the components in FIG. 4 that are the same or similar to the components of the suspension system 100 shown in FIG. 1 share the same base reference numbers, but are listed as “400” series numbers (e.g., 400, 402, 404, etc.).
- 400 series numbers
- the suspension system 400 in FIG. 4 also includes a front left damper 402 a , a front right damper 402 b , a back left damper 402 c , and a back right damper 402 d .
- the suspension system 400 also includes a manifold assembly 404 that is connected in fluid communication with a pump assembly 406 by a pump hydraulic line 408 .
- the pump assembly 406 includes a bi-directional pump 410 , a hydraulic reservoir 412 (e.g., a tank), and a bypass hydraulic line 414 that can be open and closed by a pressure relief valve 416 .
- the manifold assembly 404 is connected in fluid communication with the front and rear dampers 402 a , 402 b , 402 c , 402 d by four hydraulic circuits 420 a , 420 b , 420 c , 420 d : a first hydraulic circuit 420 a , a second hydraulic circuit 420 b , a third hydraulic circuit 420 c , and a fourth hydraulic circuit 420 d .
- the manifold assembly 404 includes four manifold valves 422 a , 422 b , 422 c , 422 d (a first manifold valve 422 a , a second manifold valve 422 b , a third manifold valve 422 c , and a fourth manifold valve 422 d ) that are connected in parallel with the pump hydraulic line 408 .
- the manifold assembly 404 further includes a first manifold comfort valve 460 a , a second manifold comfort valve 460 b , and six manifold conduits 462 a , 462 b , 462 c , 462 d , 462 e , 462 f : a first manifold conduit 462 a , a second manifold conduit 462 b , a third manifold conduit 462 c , a fourth manifold conduit 462 d , a fifth manifold conduit 462 e , and a sixth manifold conduit 462 f .
- the first manifold conduit 462 a is connected in fluid communication with the first manifold valve 422 a and the first manifold comfort valve 460 a while the second manifold conduit 462 b is connected in fluid communication with the second manifold valve 422 b and the second manifold comfort valve 460 b .
- the third manifold conduit 462 c is connected in fluid communication with the third manifold valve 422 c and the fourth manifold conduit 462 d is connected in fluid communication with the fourth manifold valve 422 d .
- the fifth manifold conduit 462 e is connected in fluid communication with the first manifold comfort valve 460 a and the sixth manifold conduit 462 f is connected in fluid communication with the second manifold comfort valve 460 b .
- fluid pressure in the four hydraulic circuits 420 a , 420 b , 420 c , 420 d operates to dynamically adjust the roll and pitch stiffness of the vehicle and can be used to either augment or completely replace mechanical stabilizer bars / anti-roll bars.
- Such mechanical systems require relatively straight, unobstructed runs between each of the front dampers 402 a , 402 b and each of the back dampers 402 c , 402 d .
- the suspension system 400 disclosed herein offers packaging benefits because the dampers 402 a , 402 b , 402 c , 402 d only need to be hydraulically connected to the manifold assembly 404 .
- the first hydraulic circuit 420 a includes a first cross-over hydraulic line 464 a that extends between and fluidly connects the compression chamber port 430 b (to the first compression chamber 426 a ) of the front left damper 402 a and the rebound chamber port 430 a (to the fourth rebound chamber 428 d ) of the back right damper 402 d .
- the first hydraulic circuit 420 a also includes a first manifold hydraulic line 438 a that extends between and fluidly connects the first cross-over hydraulic line 464 a and the first manifold conduit 462 a .
- the second hydraulic circuit 420 b includes a second cross-over hydraulic line 464 b that extends between and fluidly connects the compression chamber port 430 b (to the second compression chamber 426 b ) of the front right damper 402 b and the rebound chamber port 430 a (to the third rebound chamber 428 c ) of the back left damper 402 c .
- the second hydraulic circuit 420 b also includes a second manifold hydraulic line 438 b that extends between and fluidly connects the second cross-over hydraulic line 464 b and the second manifold conduit 462 b .
- the third hydraulic circuit 420 c includes a third cross-over hydraulic line 464 c that extends between and fluidly connects the rebound chamber port 430 a (to the first rebound chamber 428 a ) of the front left damper 402 a and the compression chamber port 430 b (to the fourth compression chamber 426 d ) of the back right damper 402 d .
- the third hydraulic circuit 420 c also includes a third manifold hydraulic line 438 c that extends between and fluidly connects the third cross-over hydraulic line 464 c and the sixth manifold conduit 462 f .
- the fourth hydraulic circuit 420 d includes a fourth cross-over hydraulic line 464 d that extends between and fluidly connects the rebound chamber port 430 a (to the second rebound chamber 428 b ) of the front right damper 402 b and the compression chamber port 430 b (to the third compression chamber 426 c ) of the back left damper 402 c .
- the fourth hydraulic circuit 420 d also includes a fourth manifold hydraulic line 438 d that extends between and fluidly connects the fourth cross-over hydraulic line 464 d and the fifth manifold conduit 462 e .
- cross-over hydraulic lines 464 a , 464 b , 464 c , 464 d simply means that the first, second, third, and fourth cross-over hydraulic lines 464 a , 464 b , 464 c , 464 d run between dampers 402 a , 402 b , 402 c , 402 d at opposite corners of the vehicle (e.g., front left to back right and front right to back left).
- the first, second, third, and fourth cross-over hydraulic lines 464 a , 464 b , 464 c , 464 d need not be linear or arranged in any particular direction as long as they ultimately connect dampers 402 a , 402 b , 402 c , 402 d positioned at opposite corners of the vehicle.
- the suspension system 400 also includes four bridge hydraulic lines 440 a , 440 b , 440 c , 440 d that fluidly couple the first and third hydraulic circuits 420 a , 420 c and the second and fourth hydraulic circuits 420 b , 420 d to one another.
- the four bridge hydraulic lines 440 a , 440 b , 440 c , 440 d include a front left bridge hydraulic line 440 a that extends between and fluidly connects the first cross-over hydraulic line 464 a and the third cross-over hydraulic line 464 c , a front right bridge hydraulic line 440 b that extends between and fluidly connects the second cross-over hydraulic line 464 b and the fourth cross-over hydraulic line 464 d , a back left bridge hydraulic line 440 c that extends between and fluidly connects the second cross-over hydraulic line 464 b and the fourth cross-over hydraulic line 464 d , and a back right bridge hydraulic line 440 d that extends between and fluidly connects the first cross-over hydraulic line 464 a and the third cross-over hydraulic line 464 c .
- the front left bridge hydraulic line 440 a is connected to the first cross-over hydraulic line 464 a between the compression chamber port 430 b of the front left damper 402 a and the first manifold hydraulic line 438 a and is connected to the third cross-over hydraulic line 464 c between the rebound chamber port 430 a of the front left damper 402 a and the third manifold hydraulic line 438 c .
- the front right bridge hydraulic line 440 b is connected to the second cross-over hydraulic line 464 b between the compression chamber port 430 b of the front right damper 402 b and the second manifold hydraulic line 438 b and is connected to the fourth cross-over hydraulic line 464 d between the rebound chamber port 430 a of the front right damper 402 b and the fourth manifold hydraulic line 438 d .
- the back left bridge hydraulic line 440 c is connected to the second cross-over hydraulic line 464 b between the rebound chamber port 430 a of the back left damper 402 c and the second manifold hydraulic line 438 b and is connected to the fourth cross-over hydraulic line 464 d between the compression chamber port 430 b of the back left damper 402 c and the fourth manifold hydraulic line 438 d .
- the back right bridge hydraulic line 440 d is connected to the first cross-over hydraulic line 464 a between the rebound chamber port 430 a of the back right damper 402 d and the first manifold hydraulic line 438 a and is connected to the third cross-over hydraulic line 464 c between the compression chamber port 430 b of the back right damper 402 d and the third manifold hydraulic line 438 c .
- the various hydraulic lines are made of flexible tubing (e.g., hydraulic hoses), but it should be appreciated that other conduit structures and/or fluid passageways can be used.
- a front left accumulator 442 a is arranged in fluid communication with the first cross-over hydraulic line 464 a at a location between the compression chamber port 430 b of the front left damper 402 a and the front left bridge hydraulic line 440 a .
- a front right accumulator 442 b is arranged in fluid communication with the second cross-over hydraulic line 464 b at a location between the compression chamber port 430 b of the front right damper 402 b and the front right bridge hydraulic line 440 b .
- a back left accumulator 442 c is arranged in fluid communication with the fourth cross-over hydraulic line 464 d at a location between the compression chamber port 430 b of the back left damper 402 c and the back left bridge hydraulic circuit 420 c .
- a back right accumulator 442 d is arranged in fluid communication with the third cross-over hydraulic line 464 c at a location between the compression chamber port 430 b of the back right damper 402 d and the back right bridge hydraulic line 440 d .
- Each of the accumulators 442 a , 442 b , 442 c , 442 d have a variable fluid volume that increases and decreases depending on the fluid pressure in the first and second longitudinal hydraulic lines 432 a , 432 b .
- the accumulators 442 a , 442 b , 442 c , 442 d may be constructed in a number of different ways.
- the accumulators 442 a , 442 b , 442 c , 442 d may have accumulation chambers and pressurized gas chambers that are separated by floating pistons or flexible membranes.
- the suspension system 400 also includes four electro-mechanical comfort valves 444 a , 444 b , 444 c , 444 d that are connected in-line (i.e., in series) with each of the bridge hydraulic lines 440 a , 440 b , 440 c , 440 d .
- a front left comfort valve 444 a is positioned in the front left bridge hydraulic line 440 a .
- a front right comfort valve 444 b is positioned in the front right bridge hydraulic line 440 b .
- a back left comfort valve 444 c is positioned in the back left bridge hydraulic line 440 c .
- a back right comfort valve 444 d is positioned in the back right bridge hydraulic line 440 d .
- the four comfort valves 444 a , 444 b , 444 c , 444 d and the two manifold comfort valves 460 a , 460 b are semi-active electro-mechanical valves with a combination of passive spring-disk elements and a solenoid.
- the comfort valves 444 a , 444 b , 444 c , 444 d and the two manifold comfort valves 460 a , 460 b are electronically connected to the controller, which is configured to supply electrical current to the solenoids of the comfort valves 444 a , 444 b , 444 c , 444 d and the two manifold comfort valves 460 a , 460 b to selectively and individually open and close the comfort valves 444 a , 444 b , 444 c , 444 d and the two manifold comfort valves 460 a , 460 b .
- the hydraulic circuits 420 a , 420 b , 420 c , 420 d operate as a closed loop system, either together or separately depending on the open or closed status of the comfort valves 444 a , 444 b , 444 c , 444 d and manifold comfort valves 460 a , 460 b .
- the bi-directional pump 110 When the manifold valves 422 a , 422 b , 422 c , 422 d are open, the bi-directional pump 110 either adds or removes fluid from one or more of the hydraulic circuits 420 a , 420 b , 420 c , 420 d .
- suspension movements There are three primary types of suspension movements that the illustrated suspension system 400 can control either passively (i.e., as a closed loop system) or actively (i.e., as an open loop system) by changing or adapting the roll and/or pitch stiffness of the vehicle: leaning to one side or the other during cornering (i.e., roll) pitching forward during braking (i.e., brake dive), and pitching aft during acceleration (i.e., rear end squat). Descriptions of how the suspension system 400 reacts to each of these conditions are provided below.
- the front right damper 402 b and back right damper 402 d begin to extend, causing fluid to flow out of the second rebound chamber 428 b of the front right damper 402 b and the fourth rebound chamber 428 d of the back right damper 402 d into the first and fourth cross-over hydraulic lines 464 a , 464 d .
- the resulting pressure difference between the dampers 402 a , 402 b , 402 c , 402 d generates damper forces that counteract or resist the roll moment of the vehicle.
- Additional roll resistance can be added by opening the first manifold valve 422 a and the first manifold comfort valve 460 a as the bi-directional pump 410 is running in a first direction where the bi-directional pump 410 draws in hydraulic fluid from the reservoir hydraulic line 418 and discharges hydraulic fluid into the pump hydraulic line 408 to produce a positive pressure in the pump hydraulic line 408 , which increases fluid pressure in the first and fourth hydraulic circuits 420 a , 420 d .
- the front left damper 402 a and back left damper 402 c begin to extend, causing fluid to flow out of the first rebound chamber 428 a of the front left damper 402 a and the third rebound chamber 428 c of the back left damper 402 c into the second and third cross-over hydraulic lines 464 b , 464 c .
- Additional roll resistance can be added by opening the second manifold valve 422 b and the second manifold comfort valve 460 b as the bi-directional pump 410 is running in the first direction where the bi-directional pump 410 draws in hydraulic fluid from the reservoir hydraulic line 418 and discharges hydraulic fluid into the pump hydraulic line 408 to produce a positive pressure in the pump hydraulic line 408 , which increases fluid pressure in the second and third hydraulic circuits 420 b , 420 c .
- the back left damper 402 c and back right damper 402 d begin to extend, causing fluid to flow out of the third rebound chamber 428 c of the back left damper 402 c into the second cross-over hydraulic line 464 b and out of the fourth rebound chamber 428 d of the back right damper 402 d into the first cross-over hydraulic line 464 a .
- the fluid flow out of the third rebound chamber 428 c of the back left damper 402 c and the fourth rebound chamber 428 d of the back right damper 402 d into the first and second cross-over hydraulic lines 464 a , 464 b increases the pressure in the front left and front right accumulators 442 a , 442 b , thus providing a passive pitch resistance where it becomes increasingly more difficult to compress the front left damper 402 a and the front right damper 402 b since the first compression chamber 426 a of the front left damper 402 a and the second compression chamber 426 b of the front right damper 402 b are connected in fluid communication with the first and second hydraulic circuits 420 a , 420 b .
- the front left damper 402 a and front right damper 402 b begin to extend, causing fluid to flow out of the first rebound chamber 428 a of the front left damper 402 a into the third cross-over hydraulic line 464 c and out of the second rebound chamber 428 b of the front right damper 402 b into the fourth cross-over hydraulic line 464 d .
- the fluid flow out of the first rebound chamber 428 a of the front left damper 402 a and the second rebound chamber 428 b of the front right damper 402 b into the third and fourth cross-over hydraulic lines 464 c , 464 d increases the pressure in the back left and back right accumulators 442 c , 442 d , thus providing a passive pitch resistance where it becomes increasingly more difficult to compress the back left damper 402 c and the back right damper 402 d since the third compression chamber 426 c of the back left damper 402 c and the fourth compression chamber 426 d of the back right damper 402 d are connected in fluid communication with the third and fourth hydraulic circuits 420 c , 420 d .
- the four comfort valves 444 a , 444 b , 444 c , 444 d and the two manifold comfort valves 460 a , 460 b can be opened to enhance the ride comfort of the suspension system 400 and reduce or eliminate unwanted suspension movements resulting from the hydraulic coupling of one damper of the system to another damper of the system (e.g., where the compression of one damper causes movement and/or a dampening change in another damper).
- fluid may flow from the first compression chamber 426 a of the front left damper 402 a , into the first cross-over hydraulic line 464 a , from the first cross-over hydraulic line 464 a to the third cross-over hydraulic line 464 c by passing through the front left bridge hydraulic line 440 a and the front left comfort valve 444 a , and into the first rebound chamber 428 a of the front left damper 402 a .
- fluid can travel from the first compression chamber 426 a to the first rebound chamber 428 a of the front left damper 402 a with the only restriction coming from the dampening valves in the rebound and compression chamber ports 430 a , 430 b of the front left damper 402 a .
- the dampers 402 a , 402 b , 402 c , 402 d are effectively decoupled from one another for improved ride comfort.
- the manifold valves 422 a , 422 b , 422 c , 422 d and/or the manifold comfort valves 460 a , 460 b may be opened while the bi-directional pump 410 is running in a second direction where the bi-directional pump 410 draws in hydraulic fluid from the pump hydraulic line 408 and discharges hydraulic fluid into the reservoir hydraulic line 418 to produce a negative pressure in the pump hydraulic line 408 that reduces fluid pressure in the hydraulic circuits 420 a , 420 b , 420 c , 420 d of the suspension system 400 .
- FIG. 5 illustrates the manifold assembly 404 of the suspension system 400 in more detail.
- the manifold assembly 404 includes first and second piston bores 466 a , 466 b that slidingly receive first and second floating pistons 468 a , 468 b , respectively.
- Each floating piston 468 a , 468 b includes a piston rod 458 and first and second piston heads 470 a , 470 b that are fixably coupled to opposing ends of the piston rod 458 .
- a chamber divider 472 is fixably mounted at a midpoint of each of the first and second piston bores 466 a , 466 b .
- Each chamber divider 472 includes a through-bore that slidingly receives the piston rod 458 .
- the first piston bore 466 a is divided by the first floating piston 468 a into a first piston chamber 474 a that is arranged in fluid communication with the first manifold conduit 462 a , a second piston chamber 474 b disposed between the first piston head 470 a of the first floating piston 468 a and the chamber divider 472 in the first piston bore 466 a , a third piston chamber 474 c disposed between the second piston head 470 b of the first floating piston 468 a and the chamber divider 472 in the first piston bore 466 a , and a fourth piston chamber 474 d that is arranged in fluid communication with the fifth manifold conduit 462 e .
- the second piston bore 466 b is divided by the second floating piston 468 b into a fifth piston chamber 474 e that is arranged in fluid communication with the second manifold conduit 462 b , a sixth piston chamber 474 f disposed between the first piston head 470 a of the second floating piston 468 b and the chamber divider 472 in the second piston bore 466 b , a seventh piston chamber 474 g disposed between the second piston head 470 b of the second floating piston 468 b and the chamber divider 472 in the second piston bore 466 b , and an eighth piston chamber 474 h that is arranged in fluid communication with the sixth manifold conduit 462 f .
- biasing members e.g., springs
- biasing members may be placed in the second, third, sixth, and seventh piston chambers 474 b , 474 c , 474 f , 474 g to naturally bias the first and second floating pistons 468 a , 468 b to a centered position where the second and third piston chambers 474 b , 474 c and the sixth and seventh piston chambers 474 f , 474 g have equal volumes.
- the first manifold conduit 462 a is arranged in fluid communication with the first manifold hydraulic line 438 a
- the second manifold conduit 462 b is arranged in fluid communication with the second manifold hydraulic line 438 b
- the fifth manifold conduit 462 e is arranged in fluid communication with the fourth manifold hydraulic line 438 d
- the sixth manifold conduit 462 f is arranged in fluid communication with the third manifold hydraulic line 438 c
- the third manifold conduit 462 c is arranged in fluid communication with the second and sixth piston chambers 474 b , 474 f while the fourth manifold conduit 462 d is arranged in fluid communication with the third and seventh piston chambers 474 c , 474 g .
- fluid pressure in the fourth piston chamber 474 d and thus the fifth manifold conduit 462 e can be increased independently of the first manifold conduit 462 a by closing the first manifold comfort valve 460 a and opening the fourth manifold valve 422 d when the bi-directional pump 410 is running in the first direction, which increases pressure in the third piston chamber 474 c and urges the first floating piston 468 a to the right in FIG. 5 , decreasing the volume of the fourth piston chamber 474 d and increasing the pressure in the fourth piston chamber 474 d .
- fluid pressure in the eighth piston chamber 474 h and thus the sixth manifold conduit 462 f can be increased independently of the second manifold conduit 462 b by closing the second manifold comfort valve 460 b and opening the fourth manifold valve 422 d when the bi-directional pump 410 is running in the first direction, which increases pressure in the seventh piston chamber 474 g and urges the second floating piston 468 b to the right in FIG. 5 , decreasing the volume of the eighth piston chamber 474 h and increasing the pressure in the eighth piston chamber 474 h .
- Fluid pressure in the first piston chamber 474 a and thus the first manifold conduit 462 a can also be increased without opening the first manifold valve 422 a by actuating the first floating piston 468 a , where the first manifold comfort valve 460 a is closed and the third manifold valve 422 c is open when the bi-directional pump 410 is running in the first direction, which increases pressure in the second piston chamber 474 b and urges the first floating piston 468 a to the left in FIG. 5 , decreasing the volume of the first piston chamber 474 a and increasing the pressure in the first piston chamber 474 a .
- fluid pressure in the fifth piston chamber 474 e and the second manifold conduit 462 b can also be increased without opening the second manifold valve 422 b by actuating the second floating piston 468 b , where the second manifold comfort valve 460 b is closed and the third manifold valve 422 c is open when the bi-directional pump 410 is running in the first direction, which increases pressure in the sixth piston chamber 474 f and urges the second floating piston 468 b to the left in FIG. 5 , decreasing the volume of the fifth piston chamber 474 e and increasing the pressure in the second piston chamber 474 e .
- the manifold assembly 404 may further include a first manifold accumulator 476 a that is arranged in fluid communication with the third manifold conduit 462 c between the third manifold valve 422 c and the second and sixth piston chambers 474 b , 474 f and a second manifold accumulator 476 b that is arranged in fluid communication with the fourth manifold conduit 462 d between the third and seventh piston chambers 474 c , 474 g .
- the first and second manifold accumulators 476 a , 476 b may be constructed in a number of different ways.
- the first and second manifold accumulators 476 a , 476 b may have accumulation chambers and pressurized gas chambers that are separated by floating pistons or flexible membranes. Under braking, fluid flow within the four hydraulic circuits generates a pressure difference between the first and second manifold accumulators 476 a , 476 b , which in turn causes an increase in pressure in the front left and front right accumulators 442 a , 442 b and provides a pitch stiffness that resists the compression of the front dampers 402 a , 402 b and rebound/extension of the back dampers 402 c , 402 d .
- the bi-directional pump 410 draws in hydraulic fluid from the reservoir hydraulic line 418 and discharges hydraulic fluid into the pump hydraulic line 408 to produce a positive pressure in the pump hydraulic line 408 , which increases fluid pressure in the first and second manifold accumulators 476 a , 476 b .
- the pitch stiffness of the system can be reduced before a braking or acceleration event by running the bi-directional pump 410 in the second direction while opening the third and fourth manifold valves 422 c , 422 d .
- the manifold assembly 404 may also include six pressure sensors 424 a , 424 b , 424 c , 424 d , 424 e , 424 f : a first pressure sensor 424 a arranged to monitor fluid pressure in the first manifold conduit 462 a , a second pressure sensor 424 b arranged to monitor fluid pressure in the second manifold conduit 462 b , a third pressure sensor 424 c arranged to monitor fluid pressure in the third manifold conduit 462 c , a fourth pressure sensor 424 d arranged to monitor fluid pressure in the fourth manifold conduit 462 d , a fifth pressure sensor 424 e arranged to monitor fluid pressure in the fifth manifold conduit 462 e , and a sixth pressure sensor 424 f arranged to monitor fluid pressure in the sixth manifold conduit 462 f . While not shown in FIG. 5 , the pressure sensors 424 a , 424 b , 424 c , 424 d ,
- FIG. 6 illustrates another suspension system 600 that shares many of the same components as the suspension system 400 illustrated in FIGS. 4 and 5 , but in FIG. 6 different pump 610 and manifold assemblies 604 have been utilized. Rather than repeat the description set forth above, the following paragraphs describe the structure and function of the components in FIG. 6 that are new and/or different from those shown and described in connection with FIGS. 4 and 5 .
- the reference numbers in FIGS. 4 and 5 are “400” series numbers (e.g., 400, 402, 404, etc.) whereas the components in FIG. 6 that are the same or similar to the components of the suspension system 400 shown in FIGS. 4 and 5 share the same base reference numbers, but are listed as “600” series numbers (e.g., 600, 602, 604, etc.).
- 600 series numbers
- the pump assembly 606 illustrated in FIG. 6 includes a single direction pump 610 with an inlet port that is connected in fluid communication with the hydraulic reservoir 612 by a reservoir hydraulic line 618 and an outlet port that is connected to the pump hydraulic line 608 .
- the single direction pump 610 draws in hydraulic fluid from the reservoir hydraulic line 618 via the inlet port and discharges hydraulic fluid into the pump hydraulic line 608 via the outlet port.
- the single direction pump 610 produces a positive pressure in the pump hydraulic line 608 that can be used by manifold assembly 604 to increase fluid pressure in the suspension system 600 .
- a check valve 678 is positioned in the pump hydraulic line 608 to prevent back feed when the single direction pump 610 is turned off.
- the pump assembly 606 also includes a return hydraulic line 680 that extends from the pump hydraulic line 108 to the hydraulic reservoir 612 .
- a first pump valve 682 a is positioned in-line with the return hydraulic line 680 .
- the pump assembly 606 also includes a pump bridge hydraulic line 683 that includes a second pump valve 682 b mounted in-line with the pump bridge hydraulic line 683 .
- the pump bridge hydraulic line 683 connects to the pump hydraulic line 608 at a location between the single direct pump 610 and the check valve 678 and connects to the return hydraulic line 680 at a location between the first pump valve 682 a and the hydraulic reservoir 612 .
- fluid pressure in the pump hydraulic line 608 can be increased by turning on the pump 610 and closing the second pump valve 682 b and fluid pressure in the pump hydraulic line 608 can be decreased by turning the pump 610 off and opening the first pump valve 682 a .
- only three manifold valves 622 a , 622 b , 622 c are connected in parallel with the pump hydraulic line 608 .
- the fourth manifold valve 622 d is positioned between the first and second piston bores 666 a , 666 b and is arranged in fluid communication with the third manifold conduit 662 c on one side and the fourth manifold conduit 662 d on the other side.
- the third and fourth manifold valves 622 c , 622 d must be open while the pump 610 is running and the first and second manifold comfort valves 660 a , 660 b are closed to increase fluid pressure in the third and seventh piston chambers 674 c , 674 g , which urges the first and second floating pistons 668 a , 668 b to the right in FIG. 6 decreasing the volume of the fourth and eighth piston chambers 674 d , 674 h and increasing the pressure in the fourth and eighth piston chambers 674 d , 674 h .
- FIG. 7 illustrates another suspension system 700 that shares many of the same components as the suspension system 400 illustrated in FIGS. 4 and 5 , but in FIG. 7 a different manifold assembly 704 has been utilized. Rather than repeat the description set forth above, the following paragraphs describe the structure and function of the components in FIG. 7 that are new and/or different from those shown and described in connection with FIGS. 4 and 5 .
- the reference numbers in FIGS. 4 and 5 are “400” series numbers (e.g., 400, 402, 404, etc.) whereas the components in FIG. 7 that are the same or similar to the components of the suspension system 400 shown in FIGS. 4 and 5 share the same base reference numbers, but are listed as “700” series numbers (e.g., 700, 702, 704, etc.).
- 700 series numbers
- the manifold assembly 704 illustrated in FIG. 7 has the same components and hydraulic arrangement as the manifold assembly 404 illustrated in FIGS. 4 and 5 , but in FIG. 7 the placement of the various components of the manifold assembly 704 is different to allow the manifold assembly 704 to be packaged in the front of the vehicle between the front dampers 702 a , 702 b .
- the manifold assembly 704 illustrated in FIG. 7 includes a front left sub-assembly 784 a and a front right sub-assembly 784 b .
- the front right sub-assembly 784 b includes the first piston bore 766 a , the first floating piston 768 a , the first manifold valve 722 a , the third manifold valve 722 c , the first manifold conduit 762 a , and the fifth manifold conduit 762 e .
- the front left sub-assembly 784 a includes the second piston bore 466 b , the second floating piston 768 b , the second manifold valve 722 b , the fourth manifold valve 722 d , the second manifold conduit 762 b , and the sixth manifold conduit 762 f .
- the pump hydraulic line 708 extends between the front left and front right sub-assemblies 784 a , 784 b and splits to connect to the manifold valves 722 a , 722 b , 722 c , 722 d on either side.
- the third and fourth manifold conduits 762 c , 762 d extend laterally between the front left and front right sub-assemblies 784 a , 784 b to connect the second and sixth piston chambers 774 b , 774 f and the third and seventh piston chambers 774 c , 774 g , respectively.
- the fifth piston chamber 774 e (which is connection in fluid communication with the second manifold conduit 762 b ) is to the right of the eighth piston chamber 774 h (which is connected in fluid communication with the sixth manifold conduit 762 f ), whereas in FIGS. 4 and 5 the fifth piston chamber 474 e (which is connected in fluid communication with the second manifold conduit 462 b ) is to the left of the eighth piston chamber 474 h (which is connected in fluid communication with the sixth manifold conduit 462 f ).
- an exemplary vehicle 822 is illustrated that has been equipped with a suspension system 800 of the present disclosure.
- the vehicle 822 in FIG. 8 has been illustrated as an automobile; however, it should be appreciated that the suspension system 800 described herein is not limited to automobiles and may be used in other types of vehicles.
- the vehicle 822 has four wheels 824 .
- the suspension system 800 of the vehicle 822 includes a plurality of dampers 802 a - 802 d , with one damper 802 a - 802 d per wheel 824 , including a front left damper 802 a , a front right damper 802 b , a back left damper 802 c , and a back right damper 802 d .
- the suspension system 800 of the vehicle 822 also includes a manifold assembly 804 that is hydraulically connected to the plurality of dampers 802 a - 802 d via a plurality of hydraulic circuits 420 a - 420 d , which are shown in FIG. 4 rather than in FIG. 8 . This is because the lines in FIG.
- FIGS. 1 - 7 illustrate electrical connections (e.g., electric wiring), which is different from the lines in FIGS. 1 - 7 , which illustrate hydraulic connections (e.g., hydraulic lines and conduits).
- electrical connections e.g., electric wiring
- hydraulic connections e.g., hydraulic lines and conduits
- the electronic/electrical connections described herein are not necessarily limited to wired connections, as wireless connections between various components can also be used.
- any of the hydraulic arrangements shown in FIGS. 1 - 7 may be implemented in combination with the electrical arrangement shown in FIG. 8 .
- the manifold assembly 804 is hydraulically connected to a pump assembly 806 via a pump hydraulic line 408 (shown in FIGS. 4 and 5 ) and may include a plurality of manifold valves 422 a - 422 d (shown in FIGS. 4 and 5 ) that are configured to open and close to control fluid flow between the pump hydraulic line 408 and the hydraulic circuits 420 a - 420 d .
- the plurality of manifold valves 422 a - 422 d are electromechanical valves configured to open and close fluid flow paths formed by a plurality of manifold conduits 462 a - 462 f ) that extend through the manifold assembly 804 and hydraulically connect the pump hydraulic line 408 with the hydraulic circuits 420 a - 420 d .
- the pump assembly 806 includes a bi-directional pump 410 that is arranged in fluid communication with the pump hydraulic line 408 .
- the plurality of hydraulic circuits 420 a - 420 d include a first hydraulic circuit 420 a that extends between and fluidly connects a first compression chamber 426 a of the front left damper 802 a and a fourth rebound chamber 428 d of the back right damper 802 d , a second hydraulic circuit 420 b that extends between and fluidly connects the second compression chamber 426 b of the front right damper 402 b and the third rebound chamber 428 c of the back left damper 402 c , a third hydraulic circuit 420 c that extends between and fluidly connects a first rebound chamber 428 a of the front left damper 402 a and a fourth compression chamber 426 d of the back right damper 402 d , and a fourth hydraulic circuit 420 d that extends between and fluidly connects a second rebound chamber
- the manifold assembly 806 together with its manifold valves 422 a - 422 d , control fluid flow between the pump hydraulic line 408 (and thus the pump assembly 806 ) and the hydraulic circuits 420 a - 420 d (and thus the dampers 802 a - 802 d ).
- the suspension system 800 includes one or more onboard sensors that are configured to generate real-time vehicle data.
- the onboard sensor(s) of the suspension system 800 may include one or more pressure sensors 424 a - 424 f (as shown in FIG. 5 ) for measuring fluid pressure within the hydraulic circuits 420 a - 420 d , one or more damper displacement sensors 832 positioned at each wheel 824 of the vehicle 822 for measuring the displacement (i.e., travel) of the dampers 802 a - 802 d , and an inertial measurement unit (IMU) 836 for measuring vehicle speed and the lateral and longitudinal acceleration of the vehicle 822 .
- IMU inertial measurement unit
- the suspension system 800 also includes a suspension control unit (SCU) 830 that includes one or more processors or controllers configured to execute computer programs to control the suspension system by implementing the control methods described below and memory that is programmed with the aforementioned computer programs and control methods.
- SCU suspension control unit
- the pressure sensors 424 a - 424 f (as shown in FIG. 5 ) measure fluid pressure within the hydraulic circuits 420 a - 420 d and generate pressure sensor signals that are indicative of the fluid pressure within each of the hydraulic circuits 420 a - 420 d .
- the pressure sensors 424 a - 424 f are arranged in electronic communication with the suspension control unit (SCU) 830 such that suspension control unit (SCU) 830 can derive and monitor the fluid pressures within the hydraulic circuits 420 a - 420 d from pressure sensor signals it receives from the pressure sensors 424 a - 424 f .
- the suspension displacement sensors 832 may be mounted to the wheel knuckle, axle, control arm, swing arm, damper, or other components that support and move up and down with the wheel 824 as the wheel 824 travels over road irregularities, such as bumps and pot-holes. Alternatively, the suspension displacement sensors 832 may be mounted to the wheels 824 themselves.
- the suspension displacement sensors 832 are arranged in electronic communication with the suspension control unit (SCU) 830 and are configured to provide suspension displacement (i.e., wheel travel) data to the suspension control unit (SCU) 830 .
- the suspension displacement sensors 832 generate damper displacement signals indicative of damper displacement for each of the dampers 802 a - 802 d and the damper displacement signals are sent or relayed to the suspension control unit (SCU) 830 for processing in accordance with the control methods described below.
- SCU suspension control unit
- the inertial measurement unit (IMU) 836 is arranged in electronic communication with the suspension control unit (SCU) 830 and is configured to provide sprung mass acceleration data to the suspension control unit (SCU) 830 .
- the inertial measurement unit (IMU) 836 may include one or more accelerometers that are mounted to the vehicle body for measuring linear and/or longitudinal accelerations of the sprung mass of the vehicle 822 and one or more gyroscopes or magnetometers for providing tilt (i.e., pitch and roll angle) measurements and heading references.
- the inertial measurement unit (IMU) 836 generates a lateral acceleration signal and a longitudinal acceleration signal that are indicative of the lateral and longitudinal accelerations of the vehicle.
- the lateral acceleration signal and the longitudinal acceleration signal are sent or relayed to the suspension control unit (SCU) 830 for processing in accordance with the control methods described below.
- the suspension control unit (SCU) 830 is arranged in electronic communication with the manifold valves 422 a - 422 d (as shown in FIG. 5 ) and the pump 410 of the pump assembly 806 .
- the memory of the suspension control unit (SCU) 830 is programmed to: monitor the real-time data generated by the onboard sensor(s) 424 a - 424 f , 832 , 836 and determine (e.g., calculate) an effective stiffness (i.e., effective roll stiffness and/or effective pitch stiffness) of the suspension system 800 based on the real-time data.
- the suspension control unit (SCU) 830 can be programmed to calculate the effective roll stiffness and/or the effective pitch stiffness of the suspension system 800 in one of three ways.
- the suspension control unit (SCU) 830 can be programmed to calculate a roll moment and a pitch moment from the fluid pressure indicated by the pressure sensor signals the suspension control unit (SCU) 830 receives from the pressure sensors 424 a - 424 f in the manifold assembly 804 .
- the suspension control unit (SCU) 830 is also programmed to calculate a roll angle and a pitch angle from the damper displacement indicated by the damper displacement signals the suspension control unit (SCU) 830 receives from the damper displacement sensors 832 .
- the suspension control unit (SCU) 830 may receive signals indicative of the roll and/or pitch angles from the inertial measurement unit (IMU) 836 .
- the suspension control unit (SCU) 830 is further programmed to calculate the effective roll stiffness of the suspension system 800 by dividing the roll moment by the roll angle and/or calculate the effective pitch stiffness of the suspension system 800 by dividing the pitch moment by the pitch angle.
- the suspension control unit (SCU) can be programmed to calculate the effective roll stiffness based on the roll angle and the lateral acceleration indicated by the lateral acceleration signal the suspension control unit (SCU) 830 receives from the inertial measurement unit (IMU) 836 and/or calculate the effective pitch stiffness based on the pitch angle and the longitudinal acceleration indicated by the longitudinal acceleration signal the suspension control unit (SCU) 830 receives from the inertial measurement unit (IMU) 836 .
- the suspension control unit (SCU) 830 can be programmed to calculate the effective roll stiffness based on the roll moment and the lateral acceleration indicated by the lateral acceleration signal the suspension control unit (SCU) 830 receives from the inertial measurement unit (IMU) 836 and/or calculate the effective pitch stiffness based on the pitch moment and the longitudinal acceleration indicated by the longitudinal acceleration signal the suspension control unit (SCU) 830 receives from the inertial measurement unit (IMU) 836 .
- the memory of the suspension control unit (SCU) 830 is further programmed to determine if the effective stiffness (i.e., the effective roll stiffness and/or the effective pitch stiffness) of the suspension system 800 is above or below the target stiffness (i.e., the target roll stiffness and/or the target pitch stiffness). If the suspension control unit (SCU) 830 determines that the effective stiffness (i.e., the effective roll stiffness and/or the effective pitch stiffness) of the suspension system 800 is above or below the target stiffness (i.e., the target roll stiffness and/or the target pitch stiffness), then the programming of the suspension control unit (SCU) 830 sets a new target pressure in the memory of the suspension control unit (SCU) 830 .
- the effective stiffness i.e., the effective roll stiffness and/or the effective pitch stiffness
- the programming of the suspension control unit (SCU) 830 initiates a control regime to open the manifold valves 422 a - 422 d , energize the pump 410 in a first direction or a second direction to pump hydraulic fluid into or out of the hydraulic circuits 420 a - 420 d and manifold conduits 462 c , 462 d of the suspension system 800 until the new target pressure is reached, and then close the manifold valves 422 a - 422 d when the new target pressure is reached. More specifically, two target pressures may be utilized: one for roll and one for pitch.
- hydraulic fluid is pumped into or out of hydraulic circuits 420 a - d through manifold valves 422 a , 422 b .
- hydraulic fluid is pumped into or out of manifold conduits 462 c , 462 d through manifold valves 422 c , 422 d .
- FIG. 9 illustrates a method of controlling the suspension system 800 described above.
- the plurality of dampers 802 a - 802 d are hydraulically connected to each other and the manifold assembly 804 via a plurality of hydraulic circuits 420 a - 420 d and the manifold assembly 804 is hydraulically connected to the pump hydraulic line 408 .
- the method illustrated in FIG. 9 begins with step 900 of setting a target roll stiffness, a target pitch stiffness, and/or a target pressure for the suspension system 800 in the memory of the suspension control unit (SCU) 830 .
- SCU suspension control unit
- Steps 902 a - d illustrate various monitoring steps where the suspension control unit (SCU) 830 monitors the real-time data the suspension control unit (SCU) 830 receives from onboard sensors or systems 424 a - 424 f , 832 , 836 .
- the suspension control unit (SCU) 830 performs step 902 a of monitoring the pressure sensor signals generated by the pressure sensors 424 a - 424 f in the manifold assembly 804 and derives the fluid pressures within the hydraulic circuits 420 a - 420 d from the pressure sensor signals.
- the suspension control unit (SCU) 830 performs step 902 b of monitoring the damper displacement signals generated by the damper displacement sensors 832 and derives the damper displacement for each of the dampers 802 a - 802 d from the damper displacement signals.
- the suspension control unit (SCU) 830 also performs step 902 c of monitoring the lateral and longitudinal acceleration signals generated by the inertial measurement unit (IMU) 836 and derives the lateral and longitudinal accelerations of the vehicle 822 from the lateral and longitudinal acceleration signals.
- the suspension control unit (SCU) 830 further performs step 904 of calculating a roll moment and a pitch moment from the fluid pressure of each of the hydraulic circuits 420 a - 420 d , as indicated by the pressure sensor signal, and step 906 of calculating a roll angle and a pitch angle from the damper displacement of each damper 802 a - 802 d , as indicated by the damper displacement signals.
- the method also includes step 910 of determining an effective roll stiffness and an effective pitch stiffness.
- the suspension control unit (SCU) 830 may calculate the effective roll stiffness and the effective pitch stiffness of the suspension system 800 in a number of different ways. Three different iterations are provided in FIG. 9 as non-limiting examples. As such, it should be appreciated that there may be additional ways of calculating the effective roll stiffness and effective pitch stiffness of the suspension system 800 other than those expressly described herein that may still far within the scope of the appended claims.
- the method includes step 908 a of calculating the effective roll stiffness by dividing the roll moment by the roll angle and calculating the effective pitch stiffness by dividing the pitch moment by the pitch angle.
- the method includes step 908 b of calculating the effective roll stiffness based on the roll angle and the lateral acceleration indicated by the lateral acceleration signal and calculating the effective pitch stiffness based on the pitch angle and the longitudinal acceleration indicated by the longitudinal acceleration signal.
- the method includes step 908 c of calculating the effective roll stiffness based on the roll moment and the lateral acceleration indicated by the lateral acceleration signal and calculating the effective pitch stiffness based on the pitch moment and the longitudinal acceleration indicated by the longitudinal acceleration signal.
- step 910 After the suspension control unit (SCU) 830 determines the effective roll stiffness and/or the effective pitch stiffness at step 910 , by performing one of the calculation steps 908a-908c, the method proceeds with step 912 a of determining if the effective roll stiffness is below the target roll stiffness and determining if the effective pitch stiffness is below the target pitch stiffness. If either the effective roll stiffness is below the target roll stiffness or the effective pitch stiffness is below the target pitch stiffness, then the method proceeds to step 914 a of setting a new target pressure in the suspension control unit (SCU) 830 by making a stepwise increase to the target pressure.
- the method includes adjusting the target pressure for roll by pumping hydraulic fluid into or out of hydraulic circuits 420 a - d through manifold valves 422 a , 422 b .
- the method also includes adjusting the target pressure for pitch by pumping hydraulic fluid into or out of manifold conduits 462 c , 462 d through manifold valves 422 c , 422 d .
- step 912 b determines if the effective roll stiffness is above the target roll stiffness and determining if the effective pitch stiffness is above the target pitch stiffness. If either the effective roll stiffness is above the target roll stiffness or the effective pitch stiffness is above the target pitch stiffness, then the method proceeds to step 914 b of setting a new target pressure in the suspension control unit (SCU) 830 by making a stepwise decrease to the target pressure.
- hydraulic fluid is pulled out of the hydraulic circuits 420 a - 420 d and/or the manifold conduits 462 c , 462 d of the suspension system 800 , flows through the open manifold valve(s) 422 a - 422 d in the manifold assembly 804 , and is returned to the hydraulic reservoir 412 through the pump hydraulic line 408 and the reservoir hydraulic line 418 , which operates to reduce the fluid pressure in the hydraulic circuits 420 a - 420 d and/or the manifold conduits 462 c , 462 d of the suspension system 800 .
- Step 902 d of monitoring the pressure sensor signals generated by the pressure sensors 424 a - 424 f and deriving the fluid pressure in the hydraulic circuits 420 a - 420 d from the pressure sensor signals is performed concurrently with steps 918 a and 918 b . Regardless of whether step 918 a is performed of step 918 b , the method continues by closing the manifold valve(s) 422 a - 422 d when the new target pressure is reached.
- the method includes reiterating steps 900 - 920 until the effective roll stiffness and the effective pitch stiffness fall within a pre-determined range of the target roll stiffness and the target pitch stiffness.
- the method includes making stepwise increases or decreases to the target pressure by making incremental changes of 0.5 pounds per square inch (PSI) up or down to the target pressure.
- PSI pounds per square inch
- the method may then continue to reiterating steps 900 - 920 until the effective roll stiffness and the effective pitch stiffness are each within a plus or minus 2 percent (%) range of the target roll stiffness and the target pitch stiffness.
- Spatial and functional relationships between elements are described using various terms, including “connected,” “engaged,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “disposed.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements.
- the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”
- the direction of an arrow generally demonstrates the flow of information (such as data or instructions) that is of interest to the illustration.
- information such as data or instructions
- the arrow may point from element A to element B. This unidirectional arrow does not imply that no other information is transmitted from element B to element A.
- element B may send requests for, or receipt acknowledgements of, the information to element A.
- module may refer to, be part of, or include: an Application term Specific Integrated Circuit (ASIC); a digital, analog, or mixed analog/digital discrete circuit; a digital, analog, or mixed analog/digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system-on-chip.
- ASIC Application term Specific Integrated Circuit
- FPGA field programmable gate array
- the module may include one or more interface circuits.
- the interface circuits may include wired or wireless interfaces that are connected to a local area network (LAN), the Internet, a wide area network (WAN), or combinations thereof.
- LAN local area network
- WAN wide area network
- the functionality of any given module of the present disclosure may be distributed among multiple modules that are connected via interface circuits. For example, multiple modules may allow load balancing.
- a server (also known as remote, or cloud) module may accomplish some functionality on behalf of a client module.
- code may include software, firmware, and/or microcode, and may refer to programs, routines, functions, classes, data structures, and/or objects.
- shared processor circuit encompasses a single processor circuit that executes some or all code from multiple modules.
- group processor circuit encompasses a processor circuit that, in combination with additional processor circuits, executes some or all code from one or more modules. References to multiple processor circuits encompass multiple processor circuits on discrete dies, multiple processor circuits on a single die, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination of the above.
- shared memory circuit encompasses a single memory circuit that stores some or all code from multiple modules.
- group memory circuit encompasses a memory circuit that, in combination with additional memories, stores some or all code from one or more modules.
- the term memory circuit is a subset of the term computer-readable medium.
- the term computer-readable medium does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave); the term computer-readable medium may therefore be considered tangible and non-transitory.
- Non-limiting examples of a non-transitory, tangible computer-readable medium are nonvolatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit), volatile memory circuits (such as a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (such as an analog or digital magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray Disc).
- nonvolatile memory circuits such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit
- volatile memory circuits such as a static random access memory circuit or a dynamic random access memory circuit
- magnetic storage media such as an analog or digital magnetic tape or a hard disk drive
- optical storage media such as a CD, a DVD, or a Blu-ray Disc
- the apparatuses and methods described in this application may be partially or fully implemented by a special purpose computer created by configuring a general purpose computer to execute one or more particular functions embodied in computer programs.
- the functional blocks, flowchart components, and other elements described above serve as software specifications, which can be translated into the computer programs by the routine work of a skilled technician or programmer.
- the computer programs include processor-executable instructions that are stored on at least one non-transitory, tangible computer-readable medium.
- the computer programs may also include or rely on stored data.
- the computer programs may encompass a basic input/output system (BIOS) that interacts with hardware of the special purpose computer, device drivers that interact with particular devices of the special purpose computer, one or more operating systems, user applications, background services, background applications, etc.
- BIOS basic input/output system
- the computer programs may include: (i) descriptive text to be parsed, such as HTML (hypertext markup language), XML (extensible markup language), or JSON (JavaScript Object Notation) (ii) assembly code, (iii) object code generated from source code by a compiler, (iv) source code for execution by an interpreter, (v) source code for compilation and execution by a just-in-time compiler, etc.
- source code may be written using syntax from languages including C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5 (Hypertext Markup Language 5th revision), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic®, Lua, MATLAB, SIMULINK, and Python®.
- languages including C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5 (Hypertext Markup Language 5th revision), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic®, Lua, MATLAB, SIMU
Abstract
Description
- The present disclosure relates generally to suspension systems for motor vehicles and more particularly to suspension systems and associated control methods that resist the pitch and roll movements of a vehicle by making incremental adjustments to target pressure and stiffness.
- The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
- Suspension systems improve the ride of a vehicle by absorbing bumps and vibrations that would otherwise unsettle the vehicle body. Suspension systems also improve safety and control by improving contact between the ground and the tires of the vehicle. One drawback of suspension systems is that basic spring / damper arrangements will allow the vehicle to roll / lean right or left during cornering (e.g., in turns), pitch forward under deceleration (e.g., under braking), and pitch back under acceleration. The lateral acceleration the vehicle experiences in turns causes a roll moment where the vehicle will lean / squat to the right when turning left and to the left when turning right. The fore and aft acceleration the vehicle experiences under acceleration and braking causes a pitch moment where the vehicle will lean forward loading the front axle during braking and aft, loading the rear axle, under acceleration. These roll and pitch moments decrease grip, cornering performance, and braking performance and can also be uncomfortable to the driver and passengers. Many vehicles are equipped with stabilizer bars / anti-roll bars, which are mechanical systems that help counteract the roll moments experienced during driving. For example, anti-roll bars are typically mechanical linkages that extend laterally across the width of the vehicle between the right and left dampers. When one of the dampers extends, the anti-roll bar applies a force to the opposite damper that counteracts the roll moment of the vehicle and helps to correct the roll angle to provide flatter cornering. However, there are several draw backs associated with these mechanical systems. First, there are often packaging constraints associated with mechanical systems because a stabilizer bar / anti-roll bar requires a relatively straight, unobstructed path across the vehicle between the dampers. Second, stabilizer bars / anti-roll bars are reactive and work when the suspension starts moving (i.e. leaning). Such mechanical systems cannot be easily switched off or cancelled out when roll stiffness is not needed. Some vehicles do have stabilizer bar / anti-roll bar disconnects that may be manually or electronically actuated, but the complexity and costs associated with these systems make them ill-suited for most vehicle applications. Packaging constraints also limit the ability to provide mechanical systems that effectively limit fore and aft pitch.
- In an effort to augment or replace traditional mechanical stabilizer bars / anti-roll bars, anti-roll suspension systems are being developed that hydraulically connect two or more dampers in a hydraulic circuit where the extension of one damper produces a pressure change in the other damper(s) in the hydraulic circuit that makes it more difficult to compress the other damper(s) in the hydraulic circuit. This pressure change in the other damper(s) increases the roll and pitch stiffness of the suspension system of the vehicle. However, one problem with such systems is that the internal pressure in the hydraulic circuits, and thus the roll and pitch stiffness, changes with temperature. For example, the internal pressure in the hydraulic circuits will rise as temperature increases, which will increase the roll and pitch stiffness of the suspension system. The opposite is true for when there is a temperature decrease. Accordingly, there is a need for a suspension system that can maintain a specified target pressure and target stiffness, regardless of temperature changes, without significant spikes or drops in pressure in the hydraulic circuits as adjustments are made.
- This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
- In accordance with one aspect of the subject disclosure, a method of controlling a suspension system of a vehicle is provided. The method includes connecting a manifold assembly to a plurality of dampers via a plurality of hydraulic circuits and connecting the manifold assembly to a pump assembly via a pump hydraulic line. The manifold assembly includes one or more manifold valves that are configured to control fluid flow between the pump hydraulic line and the hydraulic circuits. The pump assembly includes a pump that is arranged in fluid communication with the pump hydraulic line. The method includes the steps of setting a target stiffness and a target pressure in a suspension control unit (SCU) of the suspension system and monitoring real-time data from one or more onboard sensors or systems. The real-time data that is monitored by the suspension control unit (SCU) includes data reflecting fluid pressure within one or more of the hydraulic circuits, damper displacement for one or more of the dampers, lateral acceleration of the vehicle, and/or longitudinal acceleration of the vehicle. The method further includes the steps of determining an effective stiffness of the suspension system based on the real-time data, determining if the effective stiffness of the suspension system is above or below the target stiffness, and setting a new target pressure in the suspension control unit (SCU) if the effective stiffness is determined to be above or below the target stiffness. The suspension control unit (SCU) performs the step of setting a new target pressure by making a stepwise decrease or increase to the target pressure, depending on whether the effective stiffness is above or below the target stiffness. Once the new target pressure has been set, the method proceeds with the steps of opening the manifold valve(s), energizing the pump in a first direction or a second direction to pump hydraulic fluid into or out of the hydraulic circuits of the suspension system until the new target pressure is reached, and closing the manifold valve(s) when the new target pressure is reached. The method then reiterates aforementioned steps until the effective stiffness falls within a pre-determined range of the target stiffness.
- In accordance with another aspect of the subject disclosure, the method of controlling the suspension system of the vehicle further includes the steps of setting a target roll stiffness, a target pitch stiffness, and the target pressure in a suspension control unit (SCU) of the suspension system and determining an effective roll stiffness and an effective pitch stiffness of the suspension system based on the real-time data. The method includes the steps of determining if the effective roll stiffness is below the target roll stiffness, determining if the effective pitch stiffness is below the target pitch stiffness, and setting a new target pressure in the suspension control unit (SCU) by making a stepwise increase to the target pressure if the effective roll stiffness is below the target roll stiffness or if the effective pitch stiffness is below the target pitch stiffness. If the suspension control unit (SCU) makes a stepwise increase to the target pressure, then the method proceeds with the steps of opening the manifold valve(s) and energizing the pump in a first direction to pump hydraulic fluid into the hydraulic circuits of the suspension system until the new target pressure is reached. The method also includes the steps of determining if the effective roll stiffness is above the target roll stiffness, determining if the effective pitch stiffness is above the target pitch stiffness, and setting a new target pressure in the suspension control unit (SCU) by making a stepwise decrease to the target pressure if the effective roll stiffness is above the target roll stiffness or if the effective pitch stiffness is above the target pitch stiffness. If the suspension control unit (SCU) makes a stepwise increase to the target pressure, then the method proceeds with the steps of opening the manifold valve(s) and energizing the pump in a second direction to pump hydraulic fluid out of the hydraulic circuits of the suspension system until the new target pressure is reached. The method proceeds with closing the manifold valve(s) when the new target pressure is reached and reiterating the aforementioned steps until the effective roll stiffness and the effective pitch stiffness fall within a pre-determined range of the target roll stiffness and the target pitch stiffness.
- In accordance with another aspect of the present disclosure, a suspension system of a vehicle is provided. The suspension system includes a manifold assembly that is connected in fluid communication with a plurality of dampers via a plurality of hydraulic circuits and that is connected in fluid communication with a pump assembly via a pump hydraulic line. The manifold assembly includes one or more manifold valves that are configured to control fluid flow between the pump hydraulic line and the hydraulic circuits. The pump assembly includes a pump that is arranged in fluid communication with the pump hydraulic line. The suspension system also includes one or more onboard sensors that are configured to generate real-time data regarding the vehicle and a suspension control unit (SCU) that is arranged in electronic communication with the manifold valve(s), the pump, and the onboard sensor(s). The suspension control unit (SCU) includes a processor and memory that is configured to monitor the real-time data generated by the onboard sensor(s) and set a target stiffness and a target pressure in the memory. The suspension control unit (SCU) is programmed to: determine an effective stiffness of the suspension system based on the real-time data, determine if the effective stiffness of the suspension system is above or below the target stiffness, set a new target pressure in the memory of the suspension control unit (SCU) if the effective stiffness is determined to be above or below the target stiffness by making a stepwise decrease or increase to the target pressure, open the manifold valve(s) when the new target pressure is set by the suspension control unit (SCU), energize the pump in a first direction or a second direction to pump hydraulic fluid into or out of the hydraulic circuits of the suspension system until the new target pressure is reached, and close the manifold valve(s) when the new target pressure is reached.
- The suspension system of the present disclosure is able to reduce / eliminate vehicle roll while cornering and vehicle pitch during acceleration and braking for improved grip, performance, handling, and braking. The reduction of roll and pitch angles improves the comfort, steering feel, agility, and stability of the vehicle. Roll and pitch control is provided by increasing or decreasing the roll and pitch stiffness of the suspension system (based on static pressure in the system). The level of roll and pitch stiffness can be adjusted by using the pump to change the static pressure in select hydraulic circuits of the suspension system. Advantageously, the suspension system and control methods described herein can address changes in the static pressure due to increases and decreases in temperature. By continuously monitoring the fluid pressure within the hydraulic circuits of the suspension system and making stepwise increases or decreases to the target pressure when the calculated effective stiffness of the suspension system is above or below the set target stiffness, the suspension system and methods described herein can deliver target roll and/or pitch stiffness more accurately and are less susceptible to temperature related fluctuations in internal pressure and stiffness.
- Other advantages of the present disclosure will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
-
FIG. 1 is a schematic diagram illustrating an exemplary suspension system of the present disclosure that includes two comfort valves that open and close the hydraulic lines connecting the two front dampers to the two rear dampers of the system; -
FIG. 2 is a schematic diagram illustrating another exemplary suspension system of the present disclosure that includes two comfort valves that open and close the hydraulic lines connecting the two front dampers to the two rear dampers of the system and a separate hydraulic lifting circuit for the two front dampers; -
FIG. 3 is a schematic diagram illustrating another exemplary suspension system of the present disclosure that includes two comfort valves that open and close the hydraulic lines connecting the two front dampers to the two rear dampers of the system and two separate hydraulic lifting circuits for the two front dampers and the two rear dampers; -
FIG. 4 is a schematic diagram illustrating another exemplary suspension system of the present disclosure that includes four hydraulic circuits connecting the front and rear dampers and an exemplary comfort valve equipped manifold assembly; -
FIG. 5 is a schematic diagram illustrating the exemplary comfort valve equipped manifold assembly illustrated inFIG. 4 ; -
FIG. 6 is a schematic diagram illustrating another exemplary suspension system of the present disclosure that includes four hydraulic circuits connecting the front and rear dampers and another exemplary comfort valve equipped manifold assembly; -
FIG. 7 is a schematic diagram illustrating another exemplary suspension system of the present disclosure that includes four hydraulic circuits connecting the front and rear dampers and another exemplary comfort valve equipped manifold assembly; -
FIG. 8 is a schematic diagram illustrating a vehicle equipped with an exemplary suspension control system in accordance with the present disclosure; and -
FIG. 9 is a flow diagram illustrating an exemplary method of controlling the exemplary suspension systems described in the present disclosure. - Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, various comfort valve equipped suspension systems are shown.
- Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
- The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
- When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
- Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
- Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
- With reference to
FIG. 1 , asuspension system 100 including a frontleft damper 102 a, a frontright damper 102 b, a backleft damper 102 c, and a backright damper 102 d. While it should be appreciated that thesuspension system 100 described herein may include a different number of dampers than those shown in the drawings, in most automotive applications, four dampers are used at each corner of a vehicle to control vertical movements of the front and rear wheels of the vehicle. Thus, the frontleft damper 102 a controls (e.g., dampens) up and down (i.e., vertical) movements of the front left wheel of the vehicle, the frontright damper 102 b controls (e.g., dampens) up and down (i.e., vertical) movements of the front right wheel of the vehicle, the back leftdamper 102 c controls (e.g., dampens) up and down (i.e., vertical) movements of the back left wheel of the vehicle, and the backright damper 102 d controls (e.g., dampens) up and down (i.e., vertical) movements of the back right wheel of the vehicle. - The
suspension system 100 also includes amanifold assembly 104 that is connected in fluid communication with apump assembly 106 by a pumphydraulic line 108. Although other configurations are possible, in the illustrated example, thepump assembly 106 includes abi-directional pump 110, a hydraulic reservoir 112 (e.g., a tank), and a bypasshydraulic line 114 that can be open and closed by apressure relief valve 116. Thebi-directional pump 110 includes a first inlet/outlet port that is connected to the pumphydraulic line 108 and a second inlet/outlet port that is connected in fluid communication with thehydraulic reservoir 112 by a reservoirhydraulic line 118. Thebi-directional pump 110 may operate (i.e., pump fluid) in two opposite directions depending on the polarity of the electricity that is supplied to thepump 110, so the first inlet/outlet port may operate as either an inlet port or an outlet port depending on the direction thebi-directional pump 110 is operating in and the same is true for the second inlet/outlet port of thebi-directional pump 110. In the example where the first inlet/outlet port is operating as an inlet port for thebi-directional pump 110 and the second inlet/outlet port is operating as an outlet port for thebi-directional pump 110, thebi-directional pump 110 draws in hydraulic fluid from the pumphydraulic line 108 via the first inlet/outlet port and discharges hydraulic fluid into the reservoirhydraulic line 118 via the second inlet/outlet port. As such, thebi-directional pump 110 produces a negative pressure in the pumphydraulic line 108 that can be used bymanifold assembly 104 to reduced fluid pressure in thesuspension system 100. In the example where the second inlet/outlet port is operating as an inlet port for thebi-directional pump 110 and the first inlet/outlet port is operating as an outlet port for thebi-directional pump 110, thebi-directional pump 110 draws in hydraulic fluid from the reservoirhydraulic line 118 via the second inlet/outlet port and discharges hydraulic fluid into the pumphydraulic line 108 via the first inlet/outlet port. As such, thebi-directional pump 110 produces a positive pressure in the pumphydraulic line 108 that can be used bymanifold assembly 104 to increase fluid pressure in thesuspension system 100. The bypasshydraulic line 114 runs from the pumphydraulic line 108 to thehydraulic reservoir 112 and bleeds fluid back into thehydraulic reservoir 112 when the pressure in the pumphydraulic line 108 exceeds a threshold pressure that causes thepressure relief valve 116 to open. - The
manifold assembly 104 is connected in fluid communication with the front andrear dampers hydraulic circuits manifold assembly 104 includes first and secondmanifold valves hydraulic line 108. The firsthydraulic circuit 120 a is connected in fluid communication with thefirst manifold valve 122 a and the secondhydraulic circuit 120 b is connected in fluid communication with thesecond manifold valve 122 b. Themanifold assembly 104 also includes afirst pressure sensor 124 a that is arranged to monitor the pressure in the firsthydraulic circuit 120 a and asecond pressure sensor 124 b that is arranged to monitor the pressure in the secondhydraulic circuit 120 b. Thebi-directional pump 110 of thepump assembly 106 and first andsecond pressure sensors manifold valves manifold assembly 104 are electrically connected to a controller (not shown), which is configured to activate (i.e., turn on in forward or reverse) thebi-directional pump 110 and electronically actuate (i.e., open and close) the first and secondmanifold valves second pressure sensors manifold valves hydraulic circuits bi-directional pump 110 is running in. - The anti-roll capabilities of the
suspension system 100 will be explained in greater detail below; however, fromFIG. 1 it should be appreciated that fluid pressure in the first and secondhydraulic circuits front dampers back dampers suspension system 100 disclosed herein offers packaging benefits because thedampers manifold assembly 104. - Each of the
dampers suspension system 100 includes a damper housing, a piston rod, and a piston that is mounted on the piston rod. The piston is arranged in sliding engagement with the inside of the damper housing such that the piston divides the damper housing into compression and rebound chambers. As such, the frontleft damper 102 a includes afirst compression chamber 126 a and afirst rebound chamber 128 a, the frontright damper 102 b includes asecond compression chamber 126 b and asecond rebound chamber 128 b, the back leftdamper 102 c includes athird compression chamber 126 c and athird rebound chamber 128 c, and the backright damper 102 d includes afourth compression chamber 126 d and afourth rebound chamber 128 d. - In each
damper dampers hydraulic circuits rebound chambers dampers dampers compression chambers dampers dampers dampers - Each
damper compression chamber ports rebound chamber port 130 a is arranged in fluid communication with therebound chamber damper second port 130 b is arranged in fluid communication with thecompression chamber damper compression chamber ports dampers dampers - The first
hydraulic circuit 120 a includes a first longitudinalhydraulic line 132 a that extends between and fluidly connects thesecond port 130 b (to thefirst compression chamber 126 a) of the frontleft damper 102 a and thesecond port 130 b (to thethird compression chamber 126 c) of the backleft damper 102 c. The firsthydraulic circuit 120 a includes a fronthydraulic line 134 a that extends between and fluidly connects the first longitudinalhydraulic line 132 a and therebound chamber port 130 a (to thesecond rebound chamber 128 b) of the frontright damper 102 b. The firsthydraulic circuit 120 a also includes a rearhydraulic line 136 a that extends between and fluidly connects the first longitudinalhydraulic line 132 a and therebound chamber port 130 a (to thefourth rebound chamber 128 d) of the backright damper 102 d. The firsthydraulic circuit 120 a further includes a first manifoldhydraulic line 138 a that extends between and fluidly connects the first longitudinalhydraulic line 132 a and thefirst manifold valve 122 a. The secondhydraulic circuit 120 b includes a second longitudinalhydraulic line 132 b that extends between and fluidly connects thecompression chamber port 130 b (to thesecond compression chamber 126 b) of the frontright damper 102 b and thecompression chamber port 130 b (to thefourth compression chamber 126 d) of the backright damper 102 d. The secondhydraulic circuit 120 b includes a fronthydraulic line 134 b that extends between and fluidly connects the second longitudinalhydraulic line 132 b and therebound chamber port 130 a (to thefirst rebound chamber 128 a) of the frontleft damper 102 a. The secondhydraulic circuit 120 b also includes a rearhydraulic line 136 b that extends between and fluidly connects the second longitudinalhydraulic line 132 b and therebound chamber port 130 a (to thethird rebound chamber 128 c) of the backleft damper 102 c. The secondhydraulic circuit 120 b further includes a second manifoldhydraulic line 138 b that extends between and fluidly connects the second longitudinalhydraulic line 132 b and thesecond manifold valve 122 b. It should be appreciated that the word “longitudinal” as used in the first and second longitudinalhydraulic lines hydraulic lines front dampers back dampers hydraulic lines front dampers back dampers - The
suspension system 100 also includes four bridgehydraulic lines hydraulic circuits hydraulic lines hydraulic line 140 a that extends between and fluidly connects the first longitudinalhydraulic line 132 a of the firsthydraulic circuit 120 a and the fronthydraulic line 134 b of the secondhydraulic circuit 120 b, a front right bridgehydraulic line 140 b that extends between and fluidly connects the fronthydraulic line 134 a of the firsthydraulic circuit 120 a and the second longitudinalhydraulic line 132 b of the secondhydraulic circuit 120 b, a back left bridgehydraulic line 140 c that extends between and fluidly connects the first longitudinalhydraulic line 132 a of the firsthydraulic circuit 120 a and the rearhydraulic line 136 b of the secondhydraulic circuit 120 b, and a back right bridgehydraulic line 140 d that extends between and fluidly connects the rearhydraulic line 136 a of the firsthydraulic circuit 120 a and the second longitudinalhydraulic line 132 b of the secondhydraulic circuit 120 b. - The front left bridge
hydraulic line 140 a is connected to the first longitudinalhydraulic line 132 a between thecompression chamber port 130 b of the frontleft damper 102 a and the fronthydraulic line 134 a of the firsthydraulic circuit 120 a. The front right bridgehydraulic line 140 b is connected to the second longitudinalhydraulic line 132 b between thecompression chamber port 130 b of the frontright damper 102 b and the fronthydraulic line 134 b of the secondhydraulic circuit 120 b. The back left bridgehydraulic line 140 c is connected to the first longitudinalhydraulic line 132 a between thecompression chamber port 130 b of the backleft damper 102 c and the rearhydraulic line 136 a of the firsthydraulic circuit 120 a. The back right bridgehydraulic line 140 d is connected to the second longitudinalhydraulic line 132 b between thecompression chamber port 130 b of the backright damper 102 d and the rearhydraulic line 136 b of the secondhydraulic circuit 120 b. In the illustrated example, the various hydraulic lines are made of flexible tubing (e.g., hydraulic hoses), but it should be appreciated that other conduit structures and/or fluid passageways can be used. - A front
left accumulator 142 a is arranged in fluid communication with the first longitudinalhydraulic line 132 a at a location between thecompression chamber port 130 b of the frontleft damper 102 a and the front left bridgehydraulic line 140 a. A frontright accumulator 142 b is arranged in fluid communication with the second longitudinalhydraulic line 132 b at a location between thecompression chamber port 130 b of the frontright damper 102 b and the front right bridgehydraulic line 140 b. A back leftaccumulator 142 c is arranged in fluid communication with the first longitudinalhydraulic line 132 a at a location between thecompression chamber port 130 b of the backleft damper 102 c and the back left bridgehydraulic line 140 c. A backright accumulator 142 d is arranged in fluid communication with the second longitudinalhydraulic line 132 b at a location between thecompression chamber port 130 b of the backright damper 102 d and the back right bridgehydraulic line 140 d. Each of theaccumulators hydraulic lines accumulators accumulators - The
suspension system 100 also includes six electro-mechanical comfort valves hydraulic lines hydraulic lines left comfort valve 144 a is positioned in the front left bridgehydraulic line 140 a. A frontright comfort valve 144 b is positioned in the front right bridgehydraulic line 140 b. A back leftcomfort valve 144 c is positioned in the back left bridgehydraulic line 140 c. A backright comfort valve 144 d is positioned in the back right bridgehydraulic line 140 d. A firstlongitudinal comfort valve 146 a is positioned in the first longitudinalhydraulic line 132 a between the front and rearhydraulic lines hydraulic circuit 120 a. A secondlongitudinal comfort valve 146 b is positioned in the second longitudinalhydraulic line 132 b between the front and rearhydraulic lines hydraulic circuit 120 b. In the illustrated example, thecomfort valves longitudinal comfort valves comfort valves longitudinal comfort valves comfort valves longitudinal comfort valves comfort valves longitudinal comfort valves - The
first pressure sensor 124 a of themanifold assembly 104 is arranged to measure fluid pressure in the first manifoldhydraulic line 138 a and thesecond pressure sensor 124 b of themanifold assembly 104 is arranged to measure fluid pressure in the second manifoldhydraulic line 138 b. When the vehicle is cornering, braking, or accelerating, the lateral and longitudinal acceleration is measured by one or more accelerometers (not shown) and the anti-roll torque to control the roll of the vehicle is calculated by the controller. Alternatively, the lateral and longitudinal acceleration of the vehicle can be computed by the controller based on a variety of different inputs, including without limitation, steering angle, vehicle speed, brake pedal position, and/or accelerator pedal position. Thedampers - When the first and second
manifold valves hydraulic circuits mechanical comfort valves longitudinal comfort valves manifold valves bi-directional pump 110 either adds or removes fluid from the first and/or secondhydraulic circuits suspension system 100 can control the roll stiffness of the vehicle, which changes the degree to which the vehicle will lean to one side or the other during corning (i.e., roll) - For example, when the vehicle is put into a right-hand turn, the momentum of the sprung weight of the vehicle tends to make the vehicle lean left towards the outside of the turn, compressing the front
left damper 102 a and the backleft damper 102 c. When this occurs, fluid flows out from thefirst compression chamber 126 a of the frontleft damper 102 a and thethird compression chamber 126 c of the backleft damper 102 c into the first longitudinalhydraulic line 132 a of the firsthydraulic circuit 120 a. As a result of the weight transfer to the left side of the vehicle, the frontright damper 102 b and backright damper 102 d begin to extend, causing fluid to flow out of thesecond rebound chamber 128 b of the frontright damper 102 b and thefourth compression chamber 126 d of the backright damper 102 d into the front and rearhydraulic lines hydraulic circuit 120 a. When thecomfort valves first compression chamber 126 a of the frontleft damper 102 a, out of thethird compression chamber 126 c of the backleft damper 102 c, out of thesecond rebound chamber 128 b of the frontright damper 102 b, and out of thefourth rebound chamber 128 d of the backright damper 102 d and into the front and rearhydraulic lines hydraulic circuit 120 a increases the pressure in the front left and back leftaccumulators left damper 102 a and the backleft damper 102 c since thefirst compression chamber 126 a of the frontleft damper 102 a and thethird compression chamber 126 c of the backleft damper 102 c are connected in fluid communication with the firsthydraulic circuit 120 a. At the same time, fluid flows out of front right and backright accumulators first rebound chamber 128 a of the frontleft damper 102 a, into thethird rebound chamber 128 c of the backleft damper 102 c, into thesecond compression chamber 126 b of the frontright damper 102 b, and into thefourth compression chamber 126 d of the backright damper 102 d. The resulting pressure difference between thedampers first manifold valve 122 a as thebi-directional pump 110 is running in a first direction where thebi-directional pump 110 draws in hydraulic fluid from the reservoirhydraulic line 118 and discharges hydraulic fluid into the pumphydraulic line 108 to produce a positive pressure in the pumphydraulic line 108, which increases fluid pressure in the firsthydraulic circuit 120 a when thefirst manifold valve 122 a is open. - The opposite is true when the vehicle is put into a left-hand turn, where the momentum of the sprung weight of the vehicle tends to make the vehicle lean right towards the outside of the turn, compressing the front
right damper 102 b and the backright damper 102 d. When this occurs, fluid flows out from thesecond compression chamber 126 b of the frontright damper 102 b and thefourth compression chamber 126 d of the backright damper 102 d into the second longitudinalhydraulic line 132 b of the secondhydraulic circuit 120 b. As a result of the weight transfer to the right side of the vehicle, the frontleft damper 102 a and backleft damper 102 c begin to extend, causing fluid to flow out of thefirst rebound chamber 128 a of the frontleft damper 102 a and thethird rebound chamber 128 c of the backleft damper 102 c into the front and rearhydraulic lines hydraulic circuit 120 b. When thecomfort valves second compression chamber 126 b of the frontright damper 102 b, out of thefourth compression chamber 126 d of the backright damper 102 d, out of thefirst rebound chamber 128 a of the frontleft damper 102 a, and out of thethird rebound chamber 128 c of the backleft damper 102 c and into the front and rearhydraulic lines hydraulic circuit 120 b increases the pressure in the front right and backright accumulators right damper 102 b and the backright damper 102 d since thesecond compression chamber 126 b of the frontright damper 102 b and thefourth compression chamber 126 d of the backright damper 102 d are connected in fluid communication with the secondhydraulic circuit 120 b. At the same time, fluid flows out of front left and back leftaccumulators second rebound chamber 128 b of the frontright damper 102 b, into thefourth rebound chamber 128 d of the backright damper 102 d, into thefirst compression chamber 126 a of the frontleft damper 102 a, and into thethird compression chamber 126 c of the backleft damper 102 c. The resulting pressure difference between thedampers second manifold valve 122 b as thebi-directional pump 110 is running in the first direction where thebi-directional pump 110 draws in hydraulic fluid from the reservoirhydraulic line 118 and discharges hydraulic fluid into the pumphydraulic line 108 to produce a positive pressure in the pumphydraulic line 108, which increases fluid pressure in the secondhydraulic circuit 120 b when thesecond manifold valve 122 b is open. - It should also be appreciated that during cornering, the roll stiffness of the
front dampers rear dampers longitudinal comfort valves left damper 102 a and the backleft damper 102 c will be coupled when the firstlongitudinal comfort valve 146 a is open and decoupled when the firstlongitudinal comfort valve 146 a is closed. Similarly, the roll stiffness of the frontright damper 102 b and the backright damper 102 d will be coupled when the secondlongitudinal comfort valve 146 b is open and decoupled when the secondlongitudinal comfort valve 146 b is closed. - When roll stiffness is not required, the
comfort valves longitudinal comfort valves suspension system 100 and reduce or eliminate unwanted suspension movements resulting from the hydraulic coupling of one damper of the system to another damper of the system (e.g., where the compression of one damper causes movement and/or a dampening change in another damper). For example, when the frontleft comfort valve 144 a is open and the frontleft damper 102 a undergoes a compression stroke as the front left wheel hits a bump, fluid may flow from thefirst compression chamber 126 a of the frontleft damper 102 a, into the first longitudinalhydraulic line 132 a, from the first longitudinalhydraulic line 132 a to the fronthydraulic line 134 b of the secondhydraulic circuit 120 b by passing through the front left bridgehydraulic line 140 a and the frontleft comfort valve 144 a, and into thefirst rebound chamber 128 a of the frontleft damper 102 a. Thus, fluid can travel from thefirst compression chamber 126 a to thefirst rebound chamber 128 a of the frontleft damper 102 a with the only restriction coming from the dampening valves in the rebound andcompression chamber ports left damper 102 a. As such, when all of thecomfort valves longitudinal comfort valves dampers suspension system 100 to this “comfort mode” of operation, the first and/or secondmanifold valves bi-directional pump 110 is running in a second direction where thebi-directional pump 110 draws in hydraulic fluid from the pumphydraulic line 108 and discharges hydraulic fluid into the reservoirhydraulic line 118 to produce a negative pressure in the pumphydraulic line 108 that reduces fluid pressure in the first and/or secondhydraulic circuits -
FIG. 2 illustrates anothersuspension system 200 that shares many of the same components as thesuspension system 100 illustrated inFIG. 1 , but inFIG. 2 a frontaxle lift assembly 248 has been added. Rather than repeat the description set forth above, the following paragraphs describe the structure and function of the components inFIG. 2 that are new and/or different from those shown and described in connection withFIG. 1 . It should be appreciated that the reference numbers inFIG. 1 are “100” series numbers (e.g., 100, 102, 104, etc.) whereas the components inFIG. 2 that are the same or similar to the components of thesuspension system 100 shown inFIG. 1 share the same base reference numbers, but are listed as “200” series numbers (e.g., 200, 202, 204, etc.). Thus, the same description forelement 100 above applies toelement 200 inFIG. 2 and so on and so forth. - The front
axle lift assembly 248 illustrated inFIG. 2 includes a frontleft lifter 250 a on the frontleft damper 202 a and a frontright lifter 250 b on the frontright damper 202 b. Although other configurations are possible, in the illustrated example, the frontleft damper 202 a and the frontright damper 202 b include a frontleft coil spring 252 a and a frontright coil spring 252 b, respectively, that extend co-axially and helically about the piston rods of thefront dampers front lifters second rebound chambers front dampers manifold assembly 204 further includes a thirdmanifold valve 222 c that is connected in fluid communication with the pumphydraulic line 208. A front axle lifthydraulic line 254 a extends between and is fluidly connected to the thirdmanifold valve 222 c with the frontleft lifter 250 a and the frontright lifter 250 b. Athird pressure sensor 224 c is arranged to monitor the fluid pressure in the front axle lifthydraulic line 254 a. Eachfront lifter front lifters front lifters second rebound chambers front dampers axle lift assembly 248, the controller opens the thirdmanifold valve 222 c when thebi-directional pump 210 is running in the first direction where thebi-directional pump 210 draws in hydraulic fluid from the reservoirhydraulic line 218 and discharges hydraulic fluid into the pumphydraulic line 208 to produce a positive pressure in the pumphydraulic line 208, which increases fluid pressure in the front axle lifthydraulic line 254 a and thus thefront lifters manifold valve 222 c. It should therefore be appreciated that the frontaxle lift assembly 248 can be used to provide improved ground clearance during off-road operation or to give low riding vehicles improved ground clearance when traversing speed bumps. To deactivate the frontaxle lift assembly 248, the controller opens the thirdmanifold valve 222 c when thebi-directional pump 210 is running in the second direction where thebi-directional pump 210 draws in hydraulic fluid from the pumphydraulic line 208 and discharges hydraulic fluid into the reservoirhydraulic line 218 to produce a negative pressure in the pumphydraulic line 208 that reduces fluid pressure in the front axle lifthydraulic line 254 a to lower the front of the vehicle back down to an unlifted position. -
FIG. 3 illustrates anothersuspension system 300 that shares many of the same components as thesuspension systems FIGS. 1 and 2 , but inFIG. 3 a rearaxle lift assembly 356 has been added. Rather than repeat the description set forth above, the following paragraphs describe the structure and function of the components inFIG. 3 that are new and/or different from those shown and described in connection withFIGS. 1 and 2 . It should be appreciated that the reference numbers inFIG. 1 are “100” series numbers (e.g., 100, 102, 104, etc.) and the reference numbers inFIG. 2 are “200” series numbers (e.g., 200, 202, 204, etc.) whereas the components inFIG. 3 that are the same or similar to the components of thesuspension systems FIGS. 1 and 2 share the same base reference numbers, but are listed as “300” series numbers (e.g., 300, 302, 304, etc.). Thus, the same description forelements element 300 inFIG. 3 and so on and so forth. - The rear
axle lift assembly 356 illustrated inFIG. 3 includes a backleft lifter 350 c on the back leftdamper 302 c and a backright lifter 350 d on the backright damper 302 d. Although other configurations are possible, in the illustrated example, the back leftdamper 302 c and the backright damper 302 d include a backleft coil spring 352 c and a backright coil spring 352 d, respectively, that extend co-axially and helically about the piston rods of theback dampers back lifters fourth rebound chambers back dampers manifold assembly 304 further includes afourth manifold valve 322 d that is connected in fluid communication with the pumphydraulic line 308. A rear axle lifthydraulic line 354 b extends between and is fluidly connected to thefourth manifold valve 322 d with the back leftlifter 350 c and the backright lifter 350 d. Afourth pressure sensor 324 d is arranged to monitor the fluid pressure in the rear axle lifthydraulic line 354 b. Eachback lifter back lifters back lifters fourth rebound chambers back dampers axle lift assembly 356, the controller opens thefourth manifold valve 322 d when thebi-directional pump 310 is running in the first direction where thebi-directional pump 310 draws in hydraulic fluid from the reservoirhydraulic line 318 and discharges hydraulic fluid into the pumphydraulic line 308 to produce a positive pressure in the pumphydraulic line 308, which increases fluid pressure in the rear axle lifthydraulic line 354 b and thus theback lifters fourth manifold valve 322 d. It should therefore be appreciated that the rearaxle lift assembly 356 can be used in combination with the front axle lift assembly 348 (also described above in connection withFIG. 2 ) to provide improved ground clearance during off-road operation or to give low riding vehicles improved ground clearance when traversing speed bumps. To deactivate the rearaxle lift assembly 356, the controller opens the fourth manifold valve 322D when thebi-directional pump 310 is running in the second direction where thebi-directional pump 310 draws in hydraulic fluid from the pumphydraulic line 308 and discharges hydraulic fluid into the reservoirhydraulic line 318 to produces a negative pressure in the pumphydraulic line 308 that reduces fluid pressure in the rear axle lifthydraulic line 354 b to lower the rear of the vehicle back down to an unlifted position. - With reference to
FIG. 4 , anothersuspension system 400 is illustrated that shares many of the same components as thesuspension system 100 illustrated inFIG. 1 . Rather than repeat the description set forth above, the following paragraphs describe the structure and function of the components inFIG. 4 that are new and/or different from those shown and described in connection withFIG. 1 . It should be appreciated that the reference numbers inFIG. 1 are “100” series numbers (e.g., 100, 102, 104, etc.) whereas the components inFIG. 4 that are the same or similar to the components of thesuspension system 100 shown inFIG. 1 share the same base reference numbers, but are listed as “400” series numbers (e.g., 400, 402, 404, etc.). Thus, the same description forelement 100 above applies toelement 400 inFIG. 4 and so on and so forth. - The
suspension system 400 inFIG. 4 also includes a frontleft damper 402 a, a frontright damper 402 b, a backleft damper 402 c, and a backright damper 402 d. Thesuspension system 400 also includes amanifold assembly 404 that is connected in fluid communication with apump assembly 406 by a pumphydraulic line 408. Like inFIG. 1 , thepump assembly 406 includes abi-directional pump 410, a hydraulic reservoir 412 (e.g., a tank), and a bypasshydraulic line 414 that can be open and closed by apressure relief valve 416. - The
manifold assembly 404 is connected in fluid communication with the front andrear dampers hydraulic circuits hydraulic circuit 420 a, a secondhydraulic circuit 420 b, a thirdhydraulic circuit 420 c, and a fourthhydraulic circuit 420 d. Themanifold assembly 404 includes fourmanifold valves first manifold valve 422 a, asecond manifold valve 422 b, a thirdmanifold valve 422 c, and afourth manifold valve 422 d) that are connected in parallel with the pumphydraulic line 408. Themanifold assembly 404 further includes a firstmanifold comfort valve 460 a, a secondmanifold comfort valve 460 b, and sixmanifold conduits manifold conduit 462 a, a secondmanifold conduit 462 b, a thirdmanifold conduit 462 c, a fourthmanifold conduit 462 d, a fifthmanifold conduit 462 e, and a sixthmanifold conduit 462 f. The firstmanifold conduit 462 a is connected in fluid communication with thefirst manifold valve 422 a and the firstmanifold comfort valve 460 a while the secondmanifold conduit 462 b is connected in fluid communication with thesecond manifold valve 422 b and the secondmanifold comfort valve 460 b. The thirdmanifold conduit 462 c is connected in fluid communication with the thirdmanifold valve 422 c and the fourthmanifold conduit 462 d is connected in fluid communication with thefourth manifold valve 422 d. The fifthmanifold conduit 462 e is connected in fluid communication with the firstmanifold comfort valve 460 a and the sixthmanifold conduit 462 f is connected in fluid communication with the secondmanifold comfort valve 460 b. Additional structure and operational details of themanifold assembly 404 is described below in connection withFIG. 5 ; however, it should be appreciated fromFIG. 4 that fluid pressure in the fourhydraulic circuits front dampers back dampers suspension system 400 disclosed herein offers packaging benefits because thedampers manifold assembly 404. - The first
hydraulic circuit 420 a includes a first cross-overhydraulic line 464 a that extends between and fluidly connects thecompression chamber port 430 b (to thefirst compression chamber 426 a) of the frontleft damper 402 a and therebound chamber port 430 a (to thefourth rebound chamber 428 d) of the backright damper 402 d. The firsthydraulic circuit 420 a also includes a first manifoldhydraulic line 438 a that extends between and fluidly connects the first cross-overhydraulic line 464 a and the firstmanifold conduit 462 a. The secondhydraulic circuit 420 b includes a second cross-overhydraulic line 464 b that extends between and fluidly connects thecompression chamber port 430 b (to thesecond compression chamber 426 b) of the frontright damper 402 b and therebound chamber port 430 a (to thethird rebound chamber 428 c) of the backleft damper 402 c. The secondhydraulic circuit 420 b also includes a second manifoldhydraulic line 438 b that extends between and fluidly connects the second cross-overhydraulic line 464 b and the secondmanifold conduit 462 b. The thirdhydraulic circuit 420 c includes a third cross-overhydraulic line 464 c that extends between and fluidly connects therebound chamber port 430 a (to thefirst rebound chamber 428 a) of the frontleft damper 402 a and thecompression chamber port 430 b (to thefourth compression chamber 426 d) of the backright damper 402 d. The thirdhydraulic circuit 420 c also includes a third manifoldhydraulic line 438 c that extends between and fluidly connects the third cross-overhydraulic line 464 c and the sixthmanifold conduit 462 f. The fourthhydraulic circuit 420 d includes a fourth cross-overhydraulic line 464 d that extends between and fluidly connects therebound chamber port 430 a (to thesecond rebound chamber 428 b) of the frontright damper 402 b and thecompression chamber port 430 b (to thethird compression chamber 426 c) of the backleft damper 402 c. The fourthhydraulic circuit 420 d also includes a fourth manifoldhydraulic line 438 d that extends between and fluidly connects the fourth cross-overhydraulic line 464 d and the fifthmanifold conduit 462 e. It should be appreciated that the word “cross-over” as used in the first, second, third, and fourth cross-overhydraulic lines hydraulic lines dampers hydraulic lines dampers - The
suspension system 400 also includes four bridgehydraulic lines hydraulic circuits hydraulic circuits hydraulic lines hydraulic line 440 a that extends between and fluidly connects the first cross-overhydraulic line 464 a and the third cross-overhydraulic line 464 c, a front right bridgehydraulic line 440 b that extends between and fluidly connects the second cross-overhydraulic line 464 b and the fourth cross-overhydraulic line 464 d, a back left bridgehydraulic line 440 c that extends between and fluidly connects the second cross-overhydraulic line 464 b and the fourth cross-overhydraulic line 464 d, and a back right bridgehydraulic line 440 d that extends between and fluidly connects the first cross-overhydraulic line 464 a and the third cross-overhydraulic line 464 c. - The front left bridge
hydraulic line 440 a is connected to the first cross-overhydraulic line 464 a between thecompression chamber port 430 b of the frontleft damper 402 a and the first manifoldhydraulic line 438 a and is connected to the third cross-overhydraulic line 464 c between therebound chamber port 430 a of the frontleft damper 402 a and the third manifoldhydraulic line 438 c. The front right bridgehydraulic line 440 b is connected to the second cross-overhydraulic line 464 b between thecompression chamber port 430 b of the frontright damper 402 b and the second manifoldhydraulic line 438 b and is connected to the fourth cross-overhydraulic line 464 d between therebound chamber port 430 a of the frontright damper 402 b and the fourth manifoldhydraulic line 438 d. The back left bridgehydraulic line 440 c is connected to the second cross-overhydraulic line 464 b between therebound chamber port 430 a of the backleft damper 402 c and the second manifoldhydraulic line 438 b and is connected to the fourth cross-overhydraulic line 464 d between thecompression chamber port 430 b of the backleft damper 402 c and the fourth manifoldhydraulic line 438 d. The back right bridgehydraulic line 440 d is connected to the first cross-overhydraulic line 464 a between therebound chamber port 430 a of the backright damper 402 d and the first manifoldhydraulic line 438 a and is connected to the third cross-overhydraulic line 464 c between thecompression chamber port 430 b of the backright damper 402 d and the third manifoldhydraulic line 438 c. In the illustrated example, the various hydraulic lines are made of flexible tubing (e.g., hydraulic hoses), but it should be appreciated that other conduit structures and/or fluid passageways can be used. - A front
left accumulator 442 a is arranged in fluid communication with the first cross-overhydraulic line 464 a at a location between thecompression chamber port 430 b of the frontleft damper 402 a and the front left bridgehydraulic line 440 a. A frontright accumulator 442 b is arranged in fluid communication with the second cross-overhydraulic line 464 b at a location between thecompression chamber port 430 b of the frontright damper 402 b and the front right bridgehydraulic line 440 b. A back leftaccumulator 442 c is arranged in fluid communication with the fourth cross-overhydraulic line 464 d at a location between thecompression chamber port 430 b of the backleft damper 402 c and the back left bridgehydraulic circuit 420 c. A backright accumulator 442 d is arranged in fluid communication with the third cross-overhydraulic line 464 c at a location between thecompression chamber port 430 b of the backright damper 402 d and the back right bridgehydraulic line 440 d. Each of theaccumulators accumulators accumulators - The
suspension system 400 also includes four electro-mechanical comfort valves hydraulic lines left comfort valve 444 a is positioned in the front left bridgehydraulic line 440 a. A frontright comfort valve 444 b is positioned in the front right bridgehydraulic line 440 b. A back leftcomfort valve 444 c is positioned in the back left bridgehydraulic line 440 c. A backright comfort valve 444 d is positioned in the back right bridgehydraulic line 440 d. In the illustrated example, the fourcomfort valves manifold comfort valves comfort valves manifold comfort valves comfort valves manifold comfort valves comfort valves manifold comfort valves - When the
manifold valves hydraulic circuits comfort valves manifold comfort valves manifold valves bi-directional pump 110 either adds or removes fluid from one or more of thehydraulic circuits suspension system 400 can control either passively (i.e., as a closed loop system) or actively (i.e., as an open loop system) by changing or adapting the roll and/or pitch stiffness of the vehicle: leaning to one side or the other during cornering (i.e., roll) pitching forward during braking (i.e., brake dive), and pitching aft during acceleration (i.e., rear end squat). Descriptions of how thesuspension system 400 reacts to each of these conditions are provided below. - When the vehicle is put into a right-hand turn, the momentum of the sprung weight of the vehicle tends to make the vehicle lean left towards the outside of the turn, compressing the front
left damper 402 a and the backleft damper 402 c. When this occurs, fluid flows out from thefirst compression chamber 426 a of the frontleft damper 402 a and thethird compression chamber 426 c of the backleft damper 402 c into the first and fourth cross-overhydraulic lines right damper 402 b and backright damper 402 d begin to extend, causing fluid to flow out of thesecond rebound chamber 428 b of the frontright damper 402 b and thefourth rebound chamber 428 d of the backright damper 402 d into the first and fourth cross-overhydraulic lines comfort valves first compression chamber 426 a of the frontleft damper 402 a, out of thethird compression chamber 426 c of the backleft damper 402 c, out of thesecond rebound chamber 428 b of the frontright damper 402 b, and out of thefourth rebound chamber 428 d of the backright damper 402 d and into the first and fourth cross-overhydraulic lines accumulators left damper 402 a and the backleft damper 402 c since thefirst compression chamber 426 a of the frontleft damper 402 a and thethird compression chamber 426 c of the backleft damper 402 c are connected in fluid communication with the first and fourthhydraulic circuits right accumulators first rebound chamber 428 a of the frontleft damper 402 a, into thethird rebound chamber 428 c of the backleft damper 402 c, into thesecond compression chamber 426 b of the frontright damper 402 b, and into thefourth compression chamber 426 d of the backright damper 402 d. The resulting pressure difference between thedampers first manifold valve 422 a and the firstmanifold comfort valve 460 a as thebi-directional pump 410 is running in a first direction where thebi-directional pump 410 draws in hydraulic fluid from the reservoirhydraulic line 418 and discharges hydraulic fluid into the pumphydraulic line 408 to produce a positive pressure in the pumphydraulic line 408, which increases fluid pressure in the first and fourthhydraulic circuits - The opposite is true when the vehicle is put into a left-hand turn, where the momentum of the sprung weight of the vehicle tends to make the vehicle lean right towards the outside of the turn, compressing the front
right damper 402 b and the backright damper 402 d. When this occurs, fluid flows out from thesecond compression chamber 426 b of the frontright damper 402 b and thefourth compression chamber 426 d of the backright damper 402 d into the second and third cross-overhydraulic lines left damper 402 a and backleft damper 402 c begin to extend, causing fluid to flow out of thefirst rebound chamber 428 a of the frontleft damper 402 a and thethird rebound chamber 428 c of the backleft damper 402 c into the second and third cross-overhydraulic lines comfort valves second compression chamber 426 b of the frontright damper 402 b, out of thefourth compression chamber 426 d of the backright damper 402 d, out of thefirst rebound chamber 428 a of the frontleft damper 402 a, and out of thethird rebound chamber 428 c of the backleft damper 402 c and into the second and third cross-overhydraulic lines right accumulators right damper 402 b and the backright damper 402 d since thesecond compression chamber 426 b of the frontright damper 402 b and thefourth compression chamber 426 d of the backright damper 402 d are connected in fluid communication with the second and thirdhydraulic circuits accumulators second rebound chamber 428 b of the frontright damper 402 b, into thefourth rebound chamber 428 d of the backright damper 402 d, into thefirst compression chamber 426 a of the frontleft damper 402 a, and into thethird compression chamber 426 c of the backleft damper 402 c. The resulting pressure difference between thedampers second manifold valve 422 b and the secondmanifold comfort valve 460 b as thebi-directional pump 410 is running in the first direction where thebi-directional pump 410 draws in hydraulic fluid from the reservoirhydraulic line 418 and discharges hydraulic fluid into the pumphydraulic line 408 to produce a positive pressure in the pumphydraulic line 408, which increases fluid pressure in the second and thirdhydraulic circuits - During braking, the momentum of the sprung weight of the vehicle tends to make the vehicle pitch or dive forward, compressing the front
left damper 402 a and the frontright damper 402 b. When this occurs, fluid flows out from thefirst compression chamber 426 a of the frontleft damper 402 a into the first cross-overhydraulic line 464 a and out from thesecond compression chamber 426 b of the frontright damper 402 b into the second cross-overhydraulic line 464 b. As a result of the weight transfer to the front of the vehicle, the back leftdamper 402 c and backright damper 402 d begin to extend, causing fluid to flow out of thethird rebound chamber 428 c of the backleft damper 402 c into the second cross-overhydraulic line 464 b and out of thefourth rebound chamber 428 d of the backright damper 402 d into the first cross-overhydraulic line 464 a. With the front left, front right, back left, and backright comfort valves manifold comfort valves third rebound chamber 428 c of the backleft damper 402 c and thefourth rebound chamber 428 d of the backright damper 402 d into the first and second cross-overhydraulic lines right accumulators left damper 402 a and the frontright damper 402 b since thefirst compression chamber 426 a of the frontleft damper 402 a and thesecond compression chamber 426 b of the frontright damper 402 b are connected in fluid communication with the first and secondhydraulic circuits - During acceleration, the momentum of the sprung weight of the vehicle tends to make the vehicle pitch or squat rearward (i.e., aft), compressing the back left
damper 402 c and the backright damper 402 d. When this occurs, fluid flows out from thethird compression chamber 426 c of the backleft damper 402 c into the fourth cross-overhydraulic line 464 d and out of thefourth compression chamber 426 d of the backright damper 402 d into the third cross-overhydraulic line 464 c. As a result of the weight transfer to the back / rear of the vehicle, the frontleft damper 402 a and frontright damper 402 b begin to extend, causing fluid to flow out of thefirst rebound chamber 428 a of the frontleft damper 402 a into the third cross-overhydraulic line 464 c and out of thesecond rebound chamber 428 b of the frontright damper 402 b into the fourth cross-overhydraulic line 464 d. With the front left, front right, back left, and backright comfort valves manifold comfort valves first rebound chamber 428 a of the frontleft damper 402 a and thesecond rebound chamber 428 b of the frontright damper 402 b into the third and fourth cross-overhydraulic lines right accumulators left damper 402 c and the backright damper 402 d since thethird compression chamber 426 c of the backleft damper 402 c and thefourth compression chamber 426 d of the backright damper 402 d are connected in fluid communication with the third and fourthhydraulic circuits - When active or passive roll and/or pitch stiffness is not required, the four
comfort valves manifold comfort valves suspension system 400 and reduce or eliminate unwanted suspension movements resulting from the hydraulic coupling of one damper of the system to another damper of the system (e.g., where the compression of one damper causes movement and/or a dampening change in another damper). For example, when the frontleft comfort valve 444 a is open and the frontleft damper 402 a undergoes a compression stroke as the front wheel hits a bump, fluid may flow from thefirst compression chamber 426 a of the frontleft damper 402 a, into the first cross-overhydraulic line 464 a, from the first cross-overhydraulic line 464 a to the third cross-overhydraulic line 464 c by passing through the front left bridgehydraulic line 440 a and the frontleft comfort valve 444 a, and into thefirst rebound chamber 428 a of the frontleft damper 402 a. Thus, fluid can travel from thefirst compression chamber 426 a to thefirst rebound chamber 428 a of the frontleft damper 402 a with the only restriction coming from the dampening valves in the rebound andcompression chamber ports left damper 402 a. As such, when all of thecomfort valves manifold comfort valves dampers suspension system 400 to this “comfort mode” of operation, themanifold valves manifold comfort valves bi-directional pump 410 is running in a second direction where thebi-directional pump 410 draws in hydraulic fluid from the pumphydraulic line 408 and discharges hydraulic fluid into the reservoirhydraulic line 418 to produce a negative pressure in the pumphydraulic line 408 that reduces fluid pressure in thehydraulic circuits suspension system 400. -
FIG. 5 illustrates themanifold assembly 404 of thesuspension system 400 in more detail. Themanifold assembly 404 includes first and second piston bores 466 a, 466 b that slidingly receive first and second floatingpistons piston piston rod 458 and first and second piston heads 470 a, 470 b that are fixably coupled to opposing ends of thepiston rod 458. Achamber divider 472 is fixably mounted at a midpoint of each of the first and second piston bores 466 a, 466 b. Eachchamber divider 472 includes a through-bore that slidingly receives thepiston rod 458. As such, the first piston bore 466 a is divided by the first floatingpiston 468 a into afirst piston chamber 474 a that is arranged in fluid communication with the firstmanifold conduit 462 a, asecond piston chamber 474 b disposed between thefirst piston head 470 a of the first floatingpiston 468 a and thechamber divider 472 in the first piston bore 466 a, athird piston chamber 474 c disposed between thesecond piston head 470 b of the first floatingpiston 468 a and thechamber divider 472 in the first piston bore 466 a, and afourth piston chamber 474 d that is arranged in fluid communication with the fifthmanifold conduit 462 e. Similarly, the second piston bore 466 b is divided by the second floatingpiston 468 b into afifth piston chamber 474 e that is arranged in fluid communication with the secondmanifold conduit 462 b, asixth piston chamber 474 f disposed between thefirst piston head 470 a of the second floatingpiston 468 b and thechamber divider 472 in the second piston bore 466 b, aseventh piston chamber 474 g disposed between thesecond piston head 470 b of the second floatingpiston 468 b and thechamber divider 472 in the second piston bore 466 b, and aneighth piston chamber 474 h that is arranged in fluid communication with the sixthmanifold conduit 462 f. Optionally, biasing members (e.g., springs) (not shown) may be placed in the second, third, sixth, andseventh piston chambers pistons third piston chambers seventh piston chambers - The first
manifold conduit 462 a is arranged in fluid communication with the first manifoldhydraulic line 438 a, the secondmanifold conduit 462 b is arranged in fluid communication with the second manifoldhydraulic line 438 b, the fifthmanifold conduit 462 e is arranged in fluid communication with the fourth manifoldhydraulic line 438 d, and the sixthmanifold conduit 462 f is arranged in fluid communication with the third manifoldhydraulic line 438 c. The thirdmanifold conduit 462 c is arranged in fluid communication with the second andsixth piston chambers manifold conduit 462 d is arranged in fluid communication with the third andseventh piston chambers fourth piston chamber 474 d and thus the fifthmanifold conduit 462 e can be increased independently of the firstmanifold conduit 462 a by closing the firstmanifold comfort valve 460 a and opening thefourth manifold valve 422 d when thebi-directional pump 410 is running in the first direction, which increases pressure in thethird piston chamber 474 c and urges the first floatingpiston 468 a to the right inFIG. 5 , decreasing the volume of thefourth piston chamber 474 d and increasing the pressure in thefourth piston chamber 474 d. Similarly, fluid pressure in theeighth piston chamber 474 h and thus the sixthmanifold conduit 462 f can be increased independently of the secondmanifold conduit 462 b by closing the secondmanifold comfort valve 460 b and opening thefourth manifold valve 422 d when thebi-directional pump 410 is running in the first direction, which increases pressure in theseventh piston chamber 474 g and urges the second floatingpiston 468 b to the right inFIG. 5 , decreasing the volume of theeighth piston chamber 474 h and increasing the pressure in theeighth piston chamber 474 h. - Fluid pressure in the
first piston chamber 474 a and thus the firstmanifold conduit 462 a can also be increased without opening thefirst manifold valve 422 a by actuating the first floatingpiston 468 a, where the firstmanifold comfort valve 460 a is closed and the thirdmanifold valve 422 c is open when thebi-directional pump 410 is running in the first direction, which increases pressure in thesecond piston chamber 474 b and urges the first floatingpiston 468 a to the left inFIG. 5 , decreasing the volume of thefirst piston chamber 474 a and increasing the pressure in thefirst piston chamber 474 a. Similarly, fluid pressure in thefifth piston chamber 474 e and the secondmanifold conduit 462 b can also be increased without opening thesecond manifold valve 422 b by actuating the second floatingpiston 468 b, where the secondmanifold comfort valve 460 b is closed and the thirdmanifold valve 422 c is open when thebi-directional pump 410 is running in the first direction, which increases pressure in thesixth piston chamber 474 f and urges the second floatingpiston 468 b to the left inFIG. 5 , decreasing the volume of thefifth piston chamber 474 e and increasing the pressure in thesecond piston chamber 474 e. - The
manifold assembly 404 may further include a firstmanifold accumulator 476 a that is arranged in fluid communication with the thirdmanifold conduit 462 c between the thirdmanifold valve 422 c and the second andsixth piston chambers manifold accumulator 476 b that is arranged in fluid communication with the fourthmanifold conduit 462 d between the third andseventh piston chambers manifold accumulators manifold accumulators manifold accumulators right accumulators front dampers back dampers manifold accumulators right accumulators front dampers back dampers manifold valves bi-directional pump 410 is running in the first direction. Thebi-directional pump 410 draws in hydraulic fluid from the reservoirhydraulic line 418 and discharges hydraulic fluid into the pumphydraulic line 408 to produce a positive pressure in the pumphydraulic line 408, which increases fluid pressure in the first and secondmanifold accumulators bi-directional pump 410 in the second direction while opening the third and fourthmanifold valves - The
manifold assembly 404 may also include sixpressure sensors first pressure sensor 424 a arranged to monitor fluid pressure in the firstmanifold conduit 462 a, asecond pressure sensor 424 b arranged to monitor fluid pressure in the secondmanifold conduit 462 b, athird pressure sensor 424 c arranged to monitor fluid pressure in the thirdmanifold conduit 462 c, afourth pressure sensor 424 d arranged to monitor fluid pressure in the fourthmanifold conduit 462 d, afifth pressure sensor 424 e arranged to monitor fluid pressure in the fifthmanifold conduit 462 e, and asixth pressure sensor 424 f arranged to monitor fluid pressure in the sixthmanifold conduit 462 f. While not shown inFIG. 5 , thepressure sensors -
FIG. 6 illustrates anothersuspension system 600 that shares many of the same components as thesuspension system 400 illustrated inFIGS. 4 and 5 , but inFIG. 6 different pump 610 and manifold assemblies 604 have been utilized. Rather than repeat the description set forth above, the following paragraphs describe the structure and function of the components inFIG. 6 that are new and/or different from those shown and described in connection withFIGS. 4 and 5 . It should be appreciated that the reference numbers inFIGS. 4 and 5 are “400” series numbers (e.g., 400, 402, 404, etc.) whereas the components inFIG. 6 that are the same or similar to the components of thesuspension system 400 shown inFIGS. 4 and 5 share the same base reference numbers, but are listed as “600” series numbers (e.g., 600, 602, 604, etc.). Thus, the same description forelement 400 above applies toelement 600 inFIG. 6 and so on and so forth. - The
pump assembly 606 illustrated inFIG. 6 includes asingle direction pump 610 with an inlet port that is connected in fluid communication with thehydraulic reservoir 612 by a reservoirhydraulic line 618 and an outlet port that is connected to the pumphydraulic line 608. In operation, thesingle direction pump 610 draws in hydraulic fluid from the reservoirhydraulic line 618 via the inlet port and discharges hydraulic fluid into the pumphydraulic line 608 via the outlet port. As such, thesingle direction pump 610 produces a positive pressure in the pumphydraulic line 608 that can be used by manifold assembly 604 to increase fluid pressure in thesuspension system 600. Acheck valve 678 is positioned in the pumphydraulic line 608 to prevent back feed when thesingle direction pump 610 is turned off. Thepump assembly 606 also includes a returnhydraulic line 680 that extends from the pumphydraulic line 108 to thehydraulic reservoir 612. Afirst pump valve 682 a is positioned in-line with the returnhydraulic line 680. Thepump assembly 606 also includes a pump bridgehydraulic line 683 that includes asecond pump valve 682 b mounted in-line with the pump bridgehydraulic line 683. The pump bridgehydraulic line 683 connects to the pumphydraulic line 608 at a location between the singledirect pump 610 and thecheck valve 678 and connects to the returnhydraulic line 680 at a location between thefirst pump valve 682 a and thehydraulic reservoir 612. In accordance with this arrangement, fluid pressure in the pumphydraulic line 608 can be increased by turning on thepump 610 and closing thesecond pump valve 682 b and fluid pressure in the pumphydraulic line 608 can be decreased by turning thepump 610 off and opening thefirst pump valve 682 a. - In the example illustrated in
FIG. 6 , only threemanifold valves first manifold valve 622 a, thesecond manifold valve 622 b, and the thirdmanifold valve 622 c) are connected in parallel with the pumphydraulic line 608. Thefourth manifold valve 622 d is positioned between the first and second piston bores 666 a, 666 b and is arranged in fluid communication with the thirdmanifold conduit 662 c on one side and the fourthmanifold conduit 662 d on the other side. Thus, to increase fluid pressure in the fifth and/or sixthmanifold conduits manifold conduits manifold valves pump 610 is running and the first and secondmanifold comfort valves seventh piston chambers pistons FIG. 6 decreasing the volume of the fourth andeighth piston chambers eighth piston chambers -
FIG. 7 illustrates anothersuspension system 700 that shares many of the same components as thesuspension system 400 illustrated inFIGS. 4 and 5 , but inFIG. 7 adifferent manifold assembly 704 has been utilized. Rather than repeat the description set forth above, the following paragraphs describe the structure and function of the components inFIG. 7 that are new and/or different from those shown and described in connection withFIGS. 4 and 5 . It should be appreciated that the reference numbers inFIGS. 4 and 5 are “400” series numbers (e.g., 400, 402, 404, etc.) whereas the components inFIG. 7 that are the same or similar to the components of thesuspension system 400 shown inFIGS. 4 and 5 share the same base reference numbers, but are listed as “700” series numbers (e.g., 700, 702, 704, etc.). Thus, the same description forelement 400 above applies toelement 700 inFIG. 7 and so on and so forth. - The
manifold assembly 704 illustrated inFIG. 7 has the same components and hydraulic arrangement as themanifold assembly 404 illustrated inFIGS. 4 and 5 , but inFIG. 7 the placement of the various components of themanifold assembly 704 is different to allow themanifold assembly 704 to be packaged in the front of the vehicle between thefront dampers 702 a, 702 b. Themanifold assembly 704 illustrated inFIG. 7 includes a frontleft sub-assembly 784 a and a frontright sub-assembly 784 b. The frontright sub-assembly 784 b includes the first piston bore 766 a, the first floatingpiston 768 a, thefirst manifold valve 722 a, the thirdmanifold valve 722 c, the firstmanifold conduit 762 a, and the fifthmanifold conduit 762 e. The frontleft sub-assembly 784 a includes the second piston bore 466 b, the second floatingpiston 768 b, thesecond manifold valve 722 b, thefourth manifold valve 722 d, the secondmanifold conduit 762 b, and the sixthmanifold conduit 762 f. The pumphydraulic line 708 extends between the front left and frontright sub-assemblies manifold valves manifold conduits right sub-assemblies sixth piston chambers seventh piston chambers piston chambers FIG. 7 is opposite from that shown inFIGS. 4 and 5 . In other words, in accordance with the arrangement shown inFIG. 7 , thefirst piston chamber 774 a (which is connected in fluid communication with the firstmanifold conduit 762 a) faces thefifth piston chamber 774 e (which is connection in fluid communication with the secondmanifold conduit 762 b). In other words, inFIG. 7 thefifth piston chamber 774 e (which is connection in fluid communication with the secondmanifold conduit 762 b) is to the right of theeighth piston chamber 774 h (which is connected in fluid communication with the sixthmanifold conduit 762 f), whereas inFIGS. 4 and 5 thefifth piston chamber 474 e (which is connected in fluid communication with the secondmanifold conduit 462 b) is to the left of theeighth piston chamber 474 h (which is connected in fluid communication with the sixthmanifold conduit 462 f). This reversal of the arrangement of thepiston chambers hydraulic lines - With reference to
FIG. 8 , anexemplary vehicle 822 is illustrated that has been equipped with asuspension system 800 of the present disclosure. Thevehicle 822 inFIG. 8 has been illustrated as an automobile; however, it should be appreciated that thesuspension system 800 described herein is not limited to automobiles and may be used in other types of vehicles. In the illustrated example, thevehicle 822 has fourwheels 824. Similarly, thesuspension system 800 of thevehicle 822 includes a plurality of dampers 802 a-802 d, with one damper 802 a-802 d perwheel 824, including a frontleft damper 802 a, a frontright damper 802 b, a backleft damper 802 c, and a backright damper 802 d. Thesuspension system 800 of thevehicle 822 also includes amanifold assembly 804 that is hydraulically connected to the plurality of dampers 802 a-802 d via a plurality of hydraulic circuits 420 a-420 d, which are shown inFIG. 4 rather than inFIG. 8 . This is because the lines inFIG. 8 illustrate electrical connections (e.g., electric wiring), which is different from the lines inFIGS. 1-7 , which illustrate hydraulic connections (e.g., hydraulic lines and conduits). However, it should be appreciated that the electronic/electrical connections described herein are not necessarily limited to wired connections, as wireless connections between various components can also be used. It should also be appreciated that any of the hydraulic arrangements shown inFIGS. 1-7 may be implemented in combination with the electrical arrangement shown inFIG. 8 . - The
manifold assembly 804 is hydraulically connected to apump assembly 806 via a pump hydraulic line 408 (shown inFIGS. 4 and 5 ) and may include a plurality of manifold valves 422 a-422 d (shown inFIGS. 4 and 5 ) that are configured to open and close to control fluid flow between the pumphydraulic line 408 and the hydraulic circuits 420 a-420 d. More specifically, the plurality of manifold valves 422 a-422 d are electromechanical valves configured to open and close fluid flow paths formed by a plurality of manifold conduits 462 a-462 f) that extend through themanifold assembly 804 and hydraulically connect the pumphydraulic line 408 with the hydraulic circuits 420 a-420 d. - As shown in
FIG. 4 , thepump assembly 806 includes abi-directional pump 410 that is arranged in fluid communication with the pumphydraulic line 408. The plurality of hydraulic circuits 420 a-420 d include a firsthydraulic circuit 420 a that extends between and fluidly connects afirst compression chamber 426 a of the frontleft damper 802 a and afourth rebound chamber 428 d of the backright damper 802 d, a secondhydraulic circuit 420 b that extends between and fluidly connects thesecond compression chamber 426 b of the frontright damper 402 b and thethird rebound chamber 428 c of the backleft damper 402 c, a thirdhydraulic circuit 420 c that extends between and fluidly connects afirst rebound chamber 428 a of the frontleft damper 402 a and afourth compression chamber 426 d of the backright damper 402 d, and a fourthhydraulic circuit 420 d that extends between and fluidly connects asecond rebound chamber 428 b of the frontright damper 402 b and athird compression chamber 426 c of the backleft damper 402 c. Thus, themanifold assembly 806, together with its manifold valves 422 a-422 d, control fluid flow between the pump hydraulic line 408 (and thus the pump assembly 806) and the hydraulic circuits 420 a-420 d (and thus the dampers 802 a-802 d). - The
suspension system 800 includes one or more onboard sensors that are configured to generate real-time vehicle data. For example, the onboard sensor(s) of thesuspension system 800 may include one or more pressure sensors 424 a-424 f (as shown inFIG. 5 ) for measuring fluid pressure within the hydraulic circuits 420 a-420 d, one or moredamper displacement sensors 832 positioned at eachwheel 824 of thevehicle 822 for measuring the displacement (i.e., travel) of the dampers 802 a-802 d, and an inertial measurement unit (IMU) 836 for measuring vehicle speed and the lateral and longitudinal acceleration of thevehicle 822. - The
suspension system 800 also includes a suspension control unit (SCU) 830 that includes one or more processors or controllers configured to execute computer programs to control the suspension system by implementing the control methods described below and memory that is programmed with the aforementioned computer programs and control methods. - The pressure sensors 424 a-424 f (as shown in
FIG. 5 ) measure fluid pressure within the hydraulic circuits 420 a-420 d and generate pressure sensor signals that are indicative of the fluid pressure within each of the hydraulic circuits 420 a-420 d. The pressure sensors 424 a-424 f are arranged in electronic communication with the suspension control unit (SCU) 830 such that suspension control unit (SCU) 830 can derive and monitor the fluid pressures within the hydraulic circuits 420 a-420 d from pressure sensor signals it receives from the pressure sensors 424 a-424 f. - The
suspension displacement sensors 832 may be mounted to the wheel knuckle, axle, control arm, swing arm, damper, or other components that support and move up and down with thewheel 824 as thewheel 824 travels over road irregularities, such as bumps and pot-holes. Alternatively, thesuspension displacement sensors 832 may be mounted to thewheels 824 themselves. Thesuspension displacement sensors 832 are arranged in electronic communication with the suspension control unit (SCU) 830 and are configured to provide suspension displacement (i.e., wheel travel) data to the suspension control unit (SCU) 830. Thesuspension displacement sensors 832 generate damper displacement signals indicative of damper displacement for each of the dampers 802 a-802 d and the damper displacement signals are sent or relayed to the suspension control unit (SCU) 830 for processing in accordance with the control methods described below. - The inertial measurement unit (IMU) 836 is arranged in electronic communication with the suspension control unit (SCU) 830 and is configured to provide sprung mass acceleration data to the suspension control unit (SCU) 830. As such, the inertial measurement unit (IMU) 836 may include one or more accelerometers that are mounted to the vehicle body for measuring linear and/or longitudinal accelerations of the sprung mass of the
vehicle 822 and one or more gyroscopes or magnetometers for providing tilt (i.e., pitch and roll angle) measurements and heading references. The inertial measurement unit (IMU) 836 generates a lateral acceleration signal and a longitudinal acceleration signal that are indicative of the lateral and longitudinal accelerations of the vehicle. The lateral acceleration signal and the longitudinal acceleration signal are sent or relayed to the suspension control unit (SCU) 830 for processing in accordance with the control methods described below. - The suspension control unit (SCU) 830 is arranged in electronic communication with the manifold valves 422 a-422 d (as shown in
FIG. 5 ) and thepump 410 of thepump assembly 806. The memory of the suspension control unit (SCU) 830 is programmed to: monitor the real-time data generated by the onboard sensor(s) 424 a-424 f, 832, 836 and determine (e.g., calculate) an effective stiffness (i.e., effective roll stiffness and/or effective pitch stiffness) of thesuspension system 800 based on the real-time data. As will also be explained in connection with the control method described below, the suspension control unit (SCU) 830 can be programmed to calculate the effective roll stiffness and/or the effective pitch stiffness of thesuspension system 800 in one of three ways. - In accordance with one arrangement, the suspension control unit (SCU) 830 can be programmed to calculate a roll moment and a pitch moment from the fluid pressure indicated by the pressure sensor signals the suspension control unit (SCU) 830 receives from the pressure sensors 424 a-424 f in the
manifold assembly 804. The suspension control unit (SCU) 830 is also programmed to calculate a roll angle and a pitch angle from the damper displacement indicated by the damper displacement signals the suspension control unit (SCU) 830 receives from thedamper displacement sensors 832. Alternatively, the suspension control unit (SCU) 830 may receive signals indicative of the roll and/or pitch angles from the inertial measurement unit (IMU) 836. The suspension control unit (SCU) 830 is further programmed to calculate the effective roll stiffness of thesuspension system 800 by dividing the roll moment by the roll angle and/or calculate the effective pitch stiffness of thesuspension system 800 by dividing the pitch moment by the pitch angle. - In accordance with another arrangement, the suspension control unit (SCU) can be programmed to calculate the effective roll stiffness based on the roll angle and the lateral acceleration indicated by the lateral acceleration signal the suspension control unit (SCU) 830 receives from the inertial measurement unit (IMU) 836 and/or calculate the effective pitch stiffness based on the pitch angle and the longitudinal acceleration indicated by the longitudinal acceleration signal the suspension control unit (SCU) 830 receives from the inertial measurement unit (IMU) 836.
- In accordance with another arrangement, the suspension control unit (SCU) 830 can be programmed to calculate the effective roll stiffness based on the roll moment and the lateral acceleration indicated by the lateral acceleration signal the suspension control unit (SCU) 830 receives from the inertial measurement unit (IMU) 836 and/or calculate the effective pitch stiffness based on the pitch moment and the longitudinal acceleration indicated by the longitudinal acceleration signal the suspension control unit (SCU) 830 receives from the inertial measurement unit (IMU) 836.
- The memory of the suspension control unit (SCU) 830 is further programmed to determine if the effective stiffness (i.e., the effective roll stiffness and/or the effective pitch stiffness) of the
suspension system 800 is above or below the target stiffness (i.e., the target roll stiffness and/or the target pitch stiffness). If the suspension control unit (SCU) 830 determines that the effective stiffness (i.e., the effective roll stiffness and/or the effective pitch stiffness) of thesuspension system 800 is above or below the target stiffness (i.e., the target roll stiffness and/or the target pitch stiffness), then the programming of the suspension control unit (SCU) 830 sets a new target pressure in the memory of the suspension control unit (SCU) 830. Then, once the new target pressure is set in the memory of the suspension control unit (SCU) 830, the programming of the suspension control unit (SCU) 830 initiates a control regime to open the manifold valves 422 a-422 d, energize thepump 410 in a first direction or a second direction to pump hydraulic fluid into or out of the hydraulic circuits 420 a-420 d andmanifold conduits suspension system 800 until the new target pressure is reached, and then close the manifold valves 422 a-422 d when the new target pressure is reached. More specifically, two target pressures may be utilized: one for roll and one for pitch. To adjust the target pressure for roll, hydraulic fluid is pumped into or out of hydraulic circuits 420 a-d throughmanifold valves manifold conduits manifold valves -
FIG. 9 illustrates a method of controlling thesuspension system 800 described above. As described above, the plurality of dampers 802 a-802 d are hydraulically connected to each other and themanifold assembly 804 via a plurality of hydraulic circuits 420 a-420 d and themanifold assembly 804 is hydraulically connected to the pumphydraulic line 408. The method illustrated inFIG. 9 begins withstep 900 of setting a target roll stiffness, a target pitch stiffness, and/or a target pressure for thesuspension system 800 in the memory of the suspension control unit (SCU) 830. Steps 902 a-d illustrate various monitoring steps where the suspension control unit (SCU) 830 monitors the real-time data the suspension control unit (SCU) 830 receives from onboard sensors or systems 424 a-424 f, 832, 836. For example, the suspension control unit (SCU) 830 performs step 902 a of monitoring the pressure sensor signals generated by the pressure sensors 424 a-424 f in themanifold assembly 804 and derives the fluid pressures within the hydraulic circuits 420 a-420 d from the pressure sensor signals. The suspension control unit (SCU) 830 performsstep 902 b of monitoring the damper displacement signals generated by thedamper displacement sensors 832 and derives the damper displacement for each of the dampers 802 a-802 d from the damper displacement signals. The suspension control unit (SCU) 830 also performsstep 902 c of monitoring the lateral and longitudinal acceleration signals generated by the inertial measurement unit (IMU) 836 and derives the lateral and longitudinal accelerations of thevehicle 822 from the lateral and longitudinal acceleration signals. The suspension control unit (SCU) 830 further performs step 904 of calculating a roll moment and a pitch moment from the fluid pressure of each of the hydraulic circuits 420 a-420 d, as indicated by the pressure sensor signal, and step 906 of calculating a roll angle and a pitch angle from the damper displacement of each damper 802 a-802 d, as indicated by the damper displacement signals. - The method also includes
step 910 of determining an effective roll stiffness and an effective pitch stiffness. As described above, the suspension control unit (SCU) 830 may calculate the effective roll stiffness and the effective pitch stiffness of thesuspension system 800 in a number of different ways. Three different iterations are provided inFIG. 9 as non-limiting examples. As such, it should be appreciated that there may be additional ways of calculating the effective roll stiffness and effective pitch stiffness of thesuspension system 800 other than those expressly described herein that may still far within the scope of the appended claims. In one example, the method includes step 908 a of calculating the effective roll stiffness by dividing the roll moment by the roll angle and calculating the effective pitch stiffness by dividing the pitch moment by the pitch angle. In another example, the method includesstep 908 b of calculating the effective roll stiffness based on the roll angle and the lateral acceleration indicated by the lateral acceleration signal and calculating the effective pitch stiffness based on the pitch angle and the longitudinal acceleration indicated by the longitudinal acceleration signal. In yet another example, the method includesstep 908 c of calculating the effective roll stiffness based on the roll moment and the lateral acceleration indicated by the lateral acceleration signal and calculating the effective pitch stiffness based on the pitch moment and the longitudinal acceleration indicated by the longitudinal acceleration signal. Thus, various combinations ofsteps 908a-808c are also possible and are within the scope of the present disclosure. - After the suspension control unit (SCU) 830 determines the effective roll stiffness and/or the effective pitch stiffness at
step 910, by performing one of thecalculation steps 908a-908c, the method proceeds withstep 912 a of determining if the effective roll stiffness is below the target roll stiffness and determining if the effective pitch stiffness is below the target pitch stiffness. If either the effective roll stiffness is below the target roll stiffness or the effective pitch stiffness is below the target pitch stiffness, then the method proceeds to step 914 a of setting a new target pressure in the suspension control unit (SCU) 830 by making a stepwise increase to the target pressure. After this stepwise increase is made to the target pressure, the method proceeds withstep 916 a of opening one or more of the manifold valves 422 a-422 d and step 918 a of energizing thepump 410 in a first direction to pump hydraulic fluid from thehydraulic reservoir 412 of thepump assembly 806 to themanifold assembly 806 where the hydraulic fluid then flows through the open manifold valve(s) 422 a-422 d and is distributed into the hydraulic circuits 420 a-420 d andmanifold conduits suspension system 800, which operates to increase the fluid pressure in the hydraulic circuits 420 a-420 d and/or themanifold conduits suspension system 800 until the new target pressure is reached. As explained above, two target pressures may be utilized: one for roll and one for pitch. The method includes adjusting the target pressure for roll by pumping hydraulic fluid into or out of hydraulic circuits 420 a-d throughmanifold valves manifold conduits manifold valves - If the suspension control unit (SCU) 830 determines that the effective roll stiffness is not below the target roll stiffness and if the effective pitch stiffness is not below the target pitch stiffness at
step 912 a, then the method proceeds to step 912 b of determining if the effective roll stiffness is above the target roll stiffness and determining if the effective pitch stiffness is above the target pitch stiffness. If either the effective roll stiffness is above the target roll stiffness or the effective pitch stiffness is above the target pitch stiffness, then the method proceeds to step 914 b of setting a new target pressure in the suspension control unit (SCU) 830 by making a stepwise decrease to the target pressure. After this stepwise decrease is made to the target pressure, the method proceeds withstep 916 b of opening one or more of the manifold valves 422 a-422 d and step 918 b of energizing thepump 410 in a second direction to pump hydraulic fluid from themanifold assembly 806 to thehydraulic reservoir 412 of thepump assembly 806 until the new target pressure is reached. When thepump 410 is run in the second direction, hydraulic fluid is pulled out of the hydraulic circuits 420 a-420 d and/or themanifold conduits suspension system 800, flows through the open manifold valve(s) 422 a-422 d in themanifold assembly 804, and is returned to thehydraulic reservoir 412 through the pumphydraulic line 408 and the reservoirhydraulic line 418, which operates to reduce the fluid pressure in the hydraulic circuits 420 a-420 d and/or themanifold conduits suspension system 800. - Step 902 d of monitoring the pressure sensor signals generated by the pressure sensors 424 a-424 f and deriving the fluid pressure in the hydraulic circuits 420 a-420 d from the pressure sensor signals is performed concurrently with
steps step 918 a is performed ofstep 918 b, the method continues by closing the manifold valve(s) 422 a-422 d when the new target pressure is reached. - The method includes reiterating steps 900-920 until the effective roll stiffness and the effective pitch stiffness fall within a pre-determined range of the target roll stiffness and the target pitch stiffness. By way of example and without limitation, the method includes making stepwise increases or decreases to the target pressure by making incremental changes of 0.5 pounds per square inch (PSI) up or down to the target pressure. The method may then continue to reiterating steps 900-920 until the effective roll stiffness and the effective pitch stiffness are each within a plus or minus 2 percent (%) range of the target roll stiffness and the target pitch stiffness.
- Many other modifications and variations of the present disclosure are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the appended claims.
- The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the present disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and/or combined with features of any of the other embodiments, even if that combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with one another remain within the scope of this disclosure.
- Spatial and functional relationships between elements (for example, between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including “connected,” “engaged,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “disposed.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”
- In the figures, the direction of an arrow, as indicated by the arrowhead, generally demonstrates the flow of information (such as data or instructions) that is of interest to the illustration. For example, when element A and element B exchange a variety of information but information transmitted from element A to element B is relevant to the illustration, the arrow may point from element A to element B. This unidirectional arrow does not imply that no other information is transmitted from element B to element A. Further, for information sent from element A to element B, element B may send requests for, or receipt acknowledgements of, the information to element A.
- In the present disclosure, including in the definitions below, the term “module” or the “controller” may be replaced with the term “circuit.” The term “module” may refer to, be part of, or include: an Application term Specific Integrated Circuit (ASIC); a digital, analog, or mixed analog/digital discrete circuit; a digital, analog, or mixed analog/digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system-on-chip.
- The module may include one or more interface circuits. In some examples, the interface circuits may include wired or wireless interfaces that are connected to a local area network (LAN), the Internet, a wide area network (WAN), or combinations thereof. The functionality of any given module of the present disclosure may be distributed among multiple modules that are connected via interface circuits. For example, multiple modules may allow load balancing. In a further example, a server (also known as remote, or cloud) module may accomplish some functionality on behalf of a client module.
- The term code, as used above, may include software, firmware, and/or microcode, and may refer to programs, routines, functions, classes, data structures, and/or objects. The term shared processor circuit encompasses a single processor circuit that executes some or all code from multiple modules. The term group processor circuit encompasses a processor circuit that, in combination with additional processor circuits, executes some or all code from one or more modules. References to multiple processor circuits encompass multiple processor circuits on discrete dies, multiple processor circuits on a single die, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination of the above. The term shared memory circuit encompasses a single memory circuit that stores some or all code from multiple modules. The term group memory circuit encompasses a memory circuit that, in combination with additional memories, stores some or all code from one or more modules.
- The term memory circuit is a subset of the term computer-readable medium. The term computer-readable medium, as used herein, does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave); the term computer-readable medium may therefore be considered tangible and non-transitory. Non-limiting examples of a non-transitory, tangible computer-readable medium are nonvolatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit), volatile memory circuits (such as a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (such as an analog or digital magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray Disc).
- The apparatuses and methods described in this application may be partially or fully implemented by a special purpose computer created by configuring a general purpose computer to execute one or more particular functions embodied in computer programs. The functional blocks, flowchart components, and other elements described above serve as software specifications, which can be translated into the computer programs by the routine work of a skilled technician or programmer.
- The computer programs include processor-executable instructions that are stored on at least one non-transitory, tangible computer-readable medium. The computer programs may also include or rely on stored data. The computer programs may encompass a basic input/output system (BIOS) that interacts with hardware of the special purpose computer, device drivers that interact with particular devices of the special purpose computer, one or more operating systems, user applications, background services, background applications, etc.
- The computer programs may include: (i) descriptive text to be parsed, such as HTML (hypertext markup language), XML (extensible markup language), or JSON (JavaScript Object Notation) (ii) assembly code, (iii) object code generated from source code by a compiler, (iv) source code for execution by an interpreter, (v) source code for compilation and execution by a just-in-time compiler, etc. As examples only, source code may be written using syntax from languages including C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5 (Hypertext Markup Language 5th revision), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic®, Lua, MATLAB, SIMULINK, and Python®.
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PCT/US2022/046037 WO2023064172A1 (en) | 2021-10-12 | 2022-10-07 | Suspension system with incremental roll and pitch stiffness control |
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US17/499,705 US11865887B2 (en) | 2021-10-12 | 2021-10-12 | Suspension system with incremental roll and pitch stiffness control |
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